I'm trying to reach my Jag mechanic but I think he's gone home for the day. Getting the following codes. Anyone have any thoughts?

P0174 - System too lean bank 2
P0300 - Random/multiple cylinder misfire detected
P1316 - Injector circuit / IDM codes detected
P1111 - Intake Air Temp(IAT) sensor circuit intermittent high voltage.

 

The first 2 code descriptions are correct, the last 2 not so much.
P1316 is misfire excess rate.
P1111 means all the emissions related tests have passed.

I would start with cleaning the MAF sensor.

 

I'd swap the fuel filter, clean the MAF sensor and check for vacuum leaks.
And P1111 does not say anything, really, It's kind of always there.

 

So I cleaned the MAF sensor and the throttle body and no change, checked for vacuum leaks but there are just a couple very minor ones.

 

Well, there should not be ANY vacuum leaks...

 

Lean bank 2 is the left side of the car, I had this recently, it was a vacuum leak on my part load breather, which is the little brittle plastic tube that comes out of the left side cam cover and disappears under the supercharger.

Whatever vacuum leaks you have, they need to be fixed. The intake manifold is the vacuum source so any vacuum leaks will bring in outside air that is both unmetered and unfiltered. Your vacuum lines need to be tight and sealed or it'll never run right.

 

Probably multiple ignition coil failed together
Get used denso set or after market rock auto sell after market for 20-25$ per piece they're working fine
Check vacuum leaks and clean the maf or disconnect it and start the car

 

Adding to Peter's comment in #5: there should be NO leaks! Using a propane torch (no flame, just gas) run it around all possible areas on the left bank and observe the idle change.

Also, if you can check water temperature on your OBD reader, check if the water temperature sensor in the cross-over pipe is working: when they fail, they stay on a cold setting or hot setting (last reading at failure) and then will send an enrichment or lean message to the ECU through the MAF connectors. See it a lot as weather turns . . . confused, the ECU screws up the fuel mixture at either cold start or as the engine warms up. This issue should affect both banks, though.

 

So update on this. My local Jag shops were backed up so I brought it to mechanic nearby, it was showing misfire on 1 and 4 and running lean on bank 2. They replaced the plugs and coils on 1 and 4 and it didn't make a difference. Then they suggested it could be fuel injectors. $1000 in at this point and decided I wasn't going back to these guys.
I brought it by one of the Jag mechanics and he had a quick look and told me to get the minor air leaks sealed as he thought that was the issue. So anyways, I stopped driving it cause it was sounding worse and worse. it's been at the other Jag Mechanic waiting for weeks for them to finally get around to it, and turns out that it was the secondary timing chain tensioners had failed after all. So I'll be replacing those and some manifold gaskets that were leaking oil and hopefully have my car back by Christmas. This bill will be $2400.

 

2400$ just for secondary tensioners ?

 

No, $600 for that. $1100 for the gaskets. Plus the work done to this point which was two hoses to fix the vacuum leak. This is Canadian dollars as well.

 

Interesting that few of us saw this issue as timing: by now, just about every car has had the tensioners replaced (or car junked). Ten years ago, secondary tensioners was the default . . .

 

Luckily it's not catastrophic when they fail on the supercharged engines.

 

It most certainly can be catastrophic on a SC engine. You were lucky.

 

I think the lower compression in a SC engine means they aren't damaged when they jump a single tooth, but the lower clearances in a NA lump means things collide at that point.

 

Greater clearance COULD possibly prevent a timing disaster. I believe however,
it would be case specific.

 

Aye I wouldn't want to test it if I was paying for the repairs.