Just got my car back from the mechanic after having the timing chains replaced. Having a minor issue with it though that the mechanic and I discussed.

While the car was broken down I had replaced the MAF with one from autozone in an offshoot chance it would fix the issue. Now that the car is running it occasionally goes into restricted performance mode and throws codes for running lean. My mechanic said he believes the issue is the MAF I got was bad. Is this possible? Thanks.

 

First look for leaks after the MAF. Start with the hose from the MAF. Those love to open up on the bottom. Even the dipstick not pushed in all the way will look like a bad MAF.

After looking for vacuum or air leaking in, turn off the engine when warmed up and unplug the MAF. Restart the engine. If the idle got better the MAF is probably bad. Shut the engine off and re-plug the MAF. Now with your fingers give the MAF a sharp tap. If it stumbles the MAF is bad. Air cleaner should be clean and if you have one of those air cleaners that use oil on the element; have a can of MAF cleaner handy.

What year and model are we talking about and what are the codes?

 

I've found that when replacing MAFs on European cars that they tend to not like after market or generic MAFs. My rover hated them anyways... The MAF you have could be bad, or what will work for most cars won't work for your Jag.

 

2000 xj8, i'll give that a try and get back mike.

 

Finally resolved this issue.

Went back to autozone and swapped out my MAF they sold me for another, also replaced the airfilter because it was dirty and needed it. I was still getting the restricted performance light off and on.

Here's where I think the issue was really resolved though. I jumped on a back road and just for fun opened it up to about 100 mph for about 5 minutes. After that point the restricted performance light hasn't been back and I've driven it 6 or 7 times for about 80 miles. Not sure if it just cleared something out or what since the car had sat for a month broke down from timing chains.