For those that find this thread first, here is the background. I've been doing a bunch of work on my 2017 R. Some of it maintenance or preventative (Euro AMP cooling upgrade install), and some of it elective and fun (VAP Exhaust install and VAP supercharger pulley upgrades). It's been a four month process, due partly to having to order various parts from the UK and partly from chasing a squeaking belt). But, the belt squeak aside, things we generally smoothly. However, in doing all those things, a fair part of the top of the engine has been apart, and the whole exhaust so I've been expected gremlins. Today, I think I got the first.

We went out to my brother-in-laws for Easter lunch today, and took the Jag. It's about 50 miles each way and I needed to get some miles on it so I can get an emissions test done so I can renew the registration. I also wanted to get more that 10-15 miles on it so I could check the transmission cooler line leaks to see how bad they are (Found the leak -- 2017 R). The drive out was great. Car ran well and sounded wonderful. Heading home, a was well until we were around half way home -- got the dreaded "Restricted Performance" indicator. No CEL though. Surprisingly, the car will maintain 70+mph, even in restricted performance mode -- so long as the road is flat. After about 10 miles, got off and stopped at a gas station. It was a reasonable location to be able to leave the car if it decided not to restart. Also... needed gas too. It restarted fine and the rest of the drive home was uneventful. And here I was starting to feel like it might be ok to take racing in a couple of weeks.

As noted, no check engine light. It has gone into restricted performance mode once before -- while idling in pre-grid at the October 2025 BBORR. That time, restarting it cleared it and there were no codes stored. With no CEL, I was expecting to get home and have nothing to go on. I haven't fired up SDD yet, but OBDLink reported a pending P2187 -- System To Lean At Idle (Bank 1). Kind of an odd code since it went into restricted performance on the freeway at 75mph. Definitely not at idle. Now, its entirely possible the two aren't related and that code has been pending since sometime after I cleared the codes generated when I was chasing the supercharger belt squeak. I have all the intakes one and off multiple times and started it and let it idle multiple times, so it wouldn't really surprise me if it had been there for a while.

Now, some general thoughts. Most of the things noted about P2187, if you google, would impact both banks -- bad/dirty MAF, intake leak, vacuum leak, etc. Those would all likely impact both cylinder banks and not just Bank 1. Obviously with just a pending code, it was obviously a quick transient and it may just not have persisted long enough to throw a code for Bank 2 (P2189). Since the CEL never came on, it certainly isn't persistent or frequently repeating. The other possibility is that it really did just impact Bank 1, which almost certainly points at fuel delivery, or exhaust/O2 sensor issues. It may well be coincidence, but I did note that when I stopped, I went ahead and filled up because I needed too. The car was below 1/4 tank, probably close to an 1/8th. The low fuel light hadn't come on yet though. That fuel has also been in the tank for close to five months. All that to say, junk in the fuel that ended up in the Bank 1 feed, is entirely plausible.

The car has run fine, even in restricted performance mode, it was running fine. Smooth at RPM (what you can get) and at idle. It's actually been running smoother than before all the work was done. Here are the common things that are pointed out for P2917:

Dirty MAF: While the mass airflow sensors were not changed in my work, they were certainly clean by appearance. The clean side of the intakes (past the air filters) was spotless.
Leaking intakes: The intake mid pipes were replaced. The intake y-pipe was not and has been off an one the car probably a dozen times. It still appears fine and seals well. It would also impact both banks.
Dirty throttle body: clean while the car was apart.
Vacuum leak: possible, but would like impact both banks equally since the entire intake flow is common to both banks.
PCV diaphrams: PCV diaphrams were replaced while the engine was apart. Unlikely to be intermittent either.
Purge valve failure: For a real failure, unlikely to be intermittent and also likely to impact both banks.
O2 sensor problem: All the O2 sensors in the car were replaced while the exhaust was apart. While one of the new ones could certainly be bad, it would be very unlikely to be intermittent in a way that wouldn't pop the CEL.
Fuel delivery: as noted above, this is certainly plausible and could impact just Bank 1.

Right now, I'm assuming the the pending P2187 and the Restricted Performance mode are not related.

So, that leaves us with the question: what the hell triggered restricted performance? The last time I connected my SDD laptop, SDD complained -- something about needing to update something or another. I didn't really need it at the time, so I haven't chased that problem yet. I doubt it matters anyway since none of the "Restricted Performance" threads I have found hint that a JLR Tech can figure out what triggered it if no codes were logged. Right now, the only thing I have to go on is that it was at the very end of a very old tank of gas.

This would be just an annoying gremlin if I wasn't supposed to go racing in two weeks...

This thread may well become yet another "Restricted Performance" thread with no real solution, but only time will tell there.

 

The old fuel, had it been stored with stabilizer in it?

 

Of course not... that would be to logical.

In all seriousness, the high age of this tank was not planned in any way. I filled up late in Oct 2025. In early Dec, I started work on the car. I figured I would be done over the Christmas holiday, or early in January as I had a full two weeks off work for the holidays. That, of course, turned out to be very wishful thinking. The car went for a drive for the first time last Thursday and yesterday was the first extended road time since it went on the lift at the beginning of Dec.

Now, for my minor rant: Not that car makers are paragons of software engineering, but if you have sensor inputs that trigger going into a "Restricted Performance" mode... log whatever the hell triggered it please.

 

Would like to contribute, but your post is extremely long and hard to follow. F-Type is an interesting choice of vehicle to build as a race/track car.

 

Racing here is open road racing -- targeting an average speed over fixed difference, on closed public highways. We aren't wheel to wheel racing. A GT style sports car is quite well suited, though we have plenty of dedicated track cars racing, as well as your average daily driver. Its more about precision at speed than raw acceleration or cornering, at least until you get the upper speed classes. The winner of the 110mph class, in October, was an F150 averaging 110.004mph over a 118 mile course. Second in the 110 class was a 2022 Corvette, 0.010 seconds behind the F150.

As for the long post... long day, trying to get all my thoughts down and pre-answer most of the "what about questions" that would get tossed in.

 

LOL, ok. Yeah man, I get ya, and can see how that played out. We start things out sometimes with the best intentions, and then plans go off the rails.

Classic ;-0

 

There is an event log in SDD. It should tell you at what mileage things happened. Don't know if that would give you a clue or not since you saw no CEL?
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What! This sounds like the type of racing I would love to do. They close public highways for hundreds of miles? I will look into "open road racing" thanks for sharing. Agree, F-Type would excel, fantastic GT car.

 

My pending P2187 is no longer pending. Took the car to get lunch today and when I started it to come home, the CEL was on.

I had OBDLink up on my phone driving both directions, but I wasn't logging the data to storage. STFT and LTFT were tracking together on both bank 1 and 2, so despite the fact that it's only throwing a code on bank 1, it's probably impacting both banks. I pulled the codes when I got home and I don't really trust the freeze frame data from OBDLink as it reports bank 1 and 2 LTFT exactly equal and bank 1 and 2 STFT exactly equal (and 0) in the freeze frame. Long term trim was registered at 23.44%...

Once I finish work today, I'm going to get SDD connected and see what it reads, before I clear any of the existing codes, then start troubleshooting.

While it would be a pain to track down, an intake/vacuum leak that is effecting both banks would be my preferred problem, I think. It is not super likely to involve taking the entire top of the engine apart again.

 

Connected the car to SDD and.. not what I was expecting.



The pedal position senor is a known issue -- I'll have to double check, but I think this car has already had it done once. Would certainly explain the Reduced Performance mode.

The original P2187 would have been on my way back from getting the alignment done. Now here is the odd part -- the freeze frame actually shows a bank 2 O2 sensor fault.

Short term fuel trim - bank 1 - (Parameter 2) Open loop - conditions not satisfied to go closed loop: Yes
Short term fuel trim - bank 1 - (Parameter 2) Closed loop - using oxygen sensor(s) as feedback for fuel control: Yes
Long term fuel trim - bank 1 - (Parameter 2) Open loop due to driving conditions (e.g. power enrichment, deceleration enleanment): No
Short term fuel trim - bank 2 - (Parameter 2) Open loop, detected system fault: Yes
Long term fuel trim - bank 2 - (Parameter 2) Closed loop, but fault with at least one oxygen sensor - may be using single oxygen sensor for fuel control

Time to do some deeper digging.

 

Ooh, the plot thickens. Definitely curious to see where this goes!

 

Go after the pedal first for the restricted performance mode for sure. Lean codes won't trigger that alone, but an APP issue for sure will.


Time for some quick electrical testing or throw a pedal at it.

 

DiscoPotato I don't know where your at as you have no location showing?

But the 2 big road races I know of are.
1-The Silver State Classic-151 miles on public roads that are closed for the event. Looks like now they are allowing "record attempt" races! This is a new addition too.
The Silver State Classic

Also in Nebraska there is the Sandhills Open Road Challenge. 55 miles in a "Rally Style" race.
Sandhills Open Road Challenge

There are number of shorter events around too. I have run the Texas Mile as it's pretty close to me and it's only a standing mile course run on an airstrip. So no turns but hey no speed limits either!
Here is a thread when I took the XJR for a few runs.
Texas Mile

When the Therock88 was still posting he also liked to race. He went to "Rantoul, IL - Omega Motorsports No Fly Zone". What's so cool about this race is it's a 1/2 mile but your racing another car for that half a mile side by side!
No Fly Zone

I looked into Bonneville as that's grand daddy of them all. But the requirements got extensive with roll cages and fire suppression systems. Plus when I talked to people who have run Bonneville they all said the same thing. You will NEVER get all the salt out and off your car! With an Aluminum bodied car I am sure the salt would get into ever nook and cranny.
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Add the Big Bend Open Road Race to that list. West Texas -- Ft Stockton to Sanderson and back. 118 miles round trip.

Once you get out of Touring class in most of these races, it can get pricey pretty quick. For BBORR, Touring covers 100, 105, and 110MPH classes. Grand Touring is 115, 120, and 125mph. Grand Touring requires a five or six point harness -- a real one that can pass a detailed tech inspection. Grand Sport requires a roll hoop or equivalent OEM rollover structure. I've start chatting with the Tech Crew about whether the roll over structure in an F-Type coupe will qualify. Getting a harness in the car will be the next big effort after all this mechanical stuff.

 

Now, back to fixing the car....

@RoverJoe Yeah, at this point I don't believe the restricted performance is related to the work that has just been done, or to the lean code. I could be proven wrong, but at the moment I think its independent.

The pedal position sensor is likely going to be a pain since it will probably be intermittent, and rarely occur, right up until it really starts failing. The "Vehicle Communications Bus A" code is a little worrying as well. I do not relish the thought of chasing a wiring problem.

But, I can chase the lean code. My plan of attack:

• Get SDD working again on my shop laptop -- Got this done last night. Ended up clean re-installing 168.
• Clear all existing codes -- Also done last night. Now a blank slate.
• Go for a logging drive -- will be looking at fuel trims and O2 sensor values/state, plus other stuff.

What was stored points to one of the left O2 sensors being faulty, or (more likely) not being plugged in. Why that didn't throw a code is beyond me at the moment, though it's possible the VAP tune could play a role since I went to 200 cell cats so the mid O2 sensor is no longer mid cat. Its possible the faulty bank 2 O2 sensor is why it didn't through a Bank 2 Lean as well -- bank 2 never went closed loop. Regardless, as quick drive will tell me what is going on. Probably don't even have to drive it if the sensor really isn't plugged in. Since I'm using QuickJacks rather than a full lift, I don't really want to put it up in the air and remove all the underbody plastic until I know I need to, even though I'm about 97% sure I need to.

I'll address the O2 sensor problem and see where that leaves me.

 

Def don't suggest you chase down the communication faults, those always show up and rarely mean anything .I agree with the plan to troubleshoot the lean faults. Datalogger on the APP when the restricted performance faults show up would be the best bet.

 

A neighbor of mine raced that regularly, with wins in the following classes, mostly in his NSX, but once in a BMW:

100 MPH
110 MPH
115 MPH
120 MPH
135 MPH
145 MPH

He talked about how much fun it was. He also ran some in Mexico.

 

Well, this evening was a mixed bag. Went for a drive to log some data -- SDD for the first half and TorquePro for the second half. I was really just looking at fuel trims and raw O2 sensor readings, so both work. Somehow I managed to not actually save the data in either logging session. Annoying is a slight understatement. I did study the SDD charts when I arrived at my destination and it looked like all the O2 sensors were reporting sane values. When I arrived, no codes had been generated. When I got home, I had both Bank 1 and Bank 2 To Lean codes pending. Both freeze frames report Bank 2 in open loop mode due to an O2 sensor fault.

Based on the freeze frame, the codes were thrown when I started up to come back home.

What I remember from the SDD charts:

Both upstream O2 sensors (Bank 1 and 2) were reporting near 0 current, but on the positive side (slightly lean). O2 sensors 2 and 3 were both reporting changing signals, and the two times I specifically looked at them, then were 0.45V and 0.37V, so just on the lean side of normal, if I remember correctly. Short term fuel trim hovered around zero, going positive and negative as my throttle inputs and the load on the car changed. I never saw it exceed about +/-5%. Long term trims, on the other hand, tell the story. After driving, both were around 30% and they were close to 40% in the freeze frames. So yeah, way lean. Since they trend down with driving (higher engine RPM), but never get close to normal, it seems like a relatively large air leak. Since it impact both banks equally, I'll start with the intake plumbing. It's been off and on the car so many times I've lost count. It is entirely possible that that one of the clamps wasn't tightened last time I put it all together.

An interesting thing is that the two freeze frames are 0.7s apart and in the first one, the MAF sensors read almost the same: 7.56kg/h (bank 1) and 7.92kg/h (bank 2). 7/10ths of a second later, bank 1 reads 6.84kh/h and bank 2 reads 8.64kg/h. The combined airflow is 15.48kg/h for both, I just wouldn't have expected that much variation between the two.

Tomorrow I shall go chasing an air leak. My plan is to start the car, with charting up on SDD and start tightening intake clamps. If that's the problem, then when I find the problem joint(s), I would expect short term trims to go rapidly negative as the engine suddenly goes rich. There aren't too many places to go looking. Three joints on either side, and the connection to the throttle body. The throttle body gasket itself is a possibility as are the two crank case breather hoses. If the intakes don't address it, then we remove the breather hoses from the intake and block those connections.

 

Can you go old school and test with a spray to find leaks? I did this at the recommendation of my tech buddy with MAF cleaner to sort an intermittent lean CEL to find the tech who I bought an XE from that had done a full coolant pipe job didn’t fully connect a vacuum hose at the back of the head. MAF cleaner supposed to be more safe than truly old school sprays/gases.

 

I will throw out there, on two cars recently where we chased a 'lean' fault after all mechanical tests passed, it ended up being the fuel rail pressure sensor going offset. I was getting nearly 40% trims, but they were false and the car was actually running way rich when it was doing it. Had tested everything twice, tons of parts replaced. Stupid rail sensor fixed it all up. Not saying that's your issue, check all the basics first, but just have to mention it. Both were older 3.0 engines, a Velar and an LR4.