Hi guys,

OK, same old issue on my 2003x-tpe 2.5, throwing lean air left bank codes, and car goes into limp mode. Here is the weird thing, if I re-set while driving, car runs like a champ, no lights or anything come back until I turn off ignition. After I turn on ignition, 5 minutes later check engine light, limp mode etc until I clear again. OBD II is now a permanent Jaguar appendage, thinking of painting it to match interior! I have checked the usual culprits, no vacuum leaks. Only thing I have not changed are the IM gaskets, is it worth $20 to change them out? I cleaned the MAP 2x with MAP spray, no difference. I was using 87 octane gas, but have since changed 1st tank, stopped knocking but same issues. Any ideas?

 

Have you reset the battery? Only use mid-grade at a minimum, I go with premium. Not worth running regular gas in these engines. You might also want to run a bottle of seafoam through your vacuum hose if you haven't ever, it will clean a lot of gunk out of your engine. Not sure if it will affect your problem but it will help an older car run better.

 

When you reset you're just covering up the fault. It gets reflagged as soon as the PCM is allowed to do it (by your laws). So you're seeing 100% expected behaviour for the fault. Despite you thinking it runs fine after a reset it actually isn't and the PCM can see it. Stop the resets and fix whatever's wrong

You'll be damaging one or both cats until fixed....