Getting RP message almost every time I take the my XK8 out, usually after medium throttle use.
Car runs smoothly and message resets after a mile or two of normal operation.
OBDII flags P0171 and P0174 and a pending P1000 - bank 1 and 2 too lean.
Inspected air intake system for any obvious cracks or splits or looseness of breather hoses, intake box and intake tube - checked TB & MAF sensor... look clean & normal.
Is it possible the crankcase vent valve is bad? Don't know if that is check-able, so I just ordered a new one; will see if that makes any difference.
The car also still has an elusive light surge at low-speeds around 1700 rpm, which I've put up with for years; related? Mystery to me.
Thoughts? Thanks!
[NOTE: just did some more reading of MANY previous threads on this issue. I will try a few more things like: clean MAF and connector, check EGR mount on TB and hose at base of TB. ALSO: I am running the original O2 sensors... should I consider having these replaced?]

 

Just went through a similar thing with my 2000. Visually the air intake tube looks ok but a smoke test revealed cracks in the plastic.

 

You mention in another thread that you're getting some oil seepage around the VVT solenoids, so the seals in the cam covers may need replacing. Part # AJ82856, but the OEM price will make you weep

There's also an O-ring on the dipstick, and one on the bottom of the tube (less likely) that could be culprits.

Try a smoke test, as Brett_in_PA notes.

 

Suggest a Scan for DTC's to see what codes are stored. If ABS wheel sensors not cleaned, try that. W/O a scan, it's a guessing game.

 

When my wife's 2006 XK8 threw those same OBDII codes back in February 2017, it turned out to be the VVT solenoid seals as Michael referenced above. They sit there and bake in the engine bay, turning hard and brittle in the process. Once they begin to weep oil, you can bet they are weeping air as well. When they do, those codes get thrown. You need two, one for each side of the engine, and they are relatively inexpensive at rockauto.com. We have owned her XK8 since early February 2012, and I believe the car is now on its fourth pair of these seals....

 

Hold on, what? A poorly sealed dipstick can cause problems?

Just when I think I'm getting the hang of things ...

 

it will suck air. You can take out the dipstick and put your hand over the hole and (usually) see a change in rpm as the a/f mixture changes.

it didn’t throw a code on my ‘02 XKR, put when I pulled out the part-load breather plug, I noticed the 2 o-rings it has were in pieces. Indicative of how baked those things can get.

Z

 

Thank you. Guess what I'm doing now (apart from listening to the cricket).

 

Hmm, it seems a snug fit but equally the top O-ring feels very hard. I shall temporarily seal it up as I am chasing an air leak. So far the village garage hasn't made time for me and a smoke test, someone is always on holiday curse them. It is that time of year .

 

Brett_in_PA .... I just looked up when I replaced the intake duct and was surprised it's been nine years and 40K ago. I'll inspect closer, but it really looked to be in good condition.

 

Thanks to everyone for some suggestions. I'll update this thread if I get some results.
I ordered two new VVT seals from Welsh (2 for $24+shipping), will put some tape around the dipstick top (and/or replace the o-ring), reinspect the intake duct and TB stuff, install the new crankcase vent valve when it arrives and superclean the MAF and contacts.
Cheers!

 

Bear in mind that a to-a-human small air leak is a BIG one to the car and would need fixing.

 

Remember, the MAF part of the removable sensor is way up inside of it. The little bulb and wiring that’s more exposed is an ambient air temperature sensor.

use a high quality MAF spray cleaner such as the CRC brand. And never touch the sensor(s) with anything other than the spray, no brush of any kind, etc.


note: it took me 3 sessions with the CRC cleaner before the sensor did a proper job. So don’t be discouraged if you don’t get results on the fuel trim numbers the first go-around. Just take it off again and give it a good dousing.

note: clean the wiring connector also with the CRC electrical cleaner.

both products are very flammable and dangerous to breathe. Use in a well ventilated area.

Z

 

This is an update to my earlier post above, regarding restricted performance issues on my '03 XK8.
As I mentioned, I ended up performing all the checks and replacements and cleanings - with no discernable results.
In a December '22 post, I mentioned I had taken the car into my Indy mechanic for a transmission check and service and was told the unit was toast. The car had a replacement transmission installed in January from a supplier in California, with about 40K on it. The swap went without issues and with minor tune-up tweaks now operates smooth as butter with none (knock on wood) of the earlier issues. Even the light surging on light throttle I have had for years is gone. So, happy, happy, happy we. The charge, out the door, was $3900.