Hello, my 1998 volvo S70 GTL posts a check engine light P0172 - generic engine runs rich. I saw the PVC systems are problems on these cars, so I replaced the whole thing with a kit from IPD. There was no change. The car definitely runs rich, and I can't find a vacuum leak anywhere and I'm running out of ideas. Odd note, the car previously gave me lean codes, I found a grain of rice sized hole in the intercooler, which I patched with epoxy. Once I patched it, it immediately started giving rich codes. I really have no idea what else it could be, if anyone has ideas that would be great. Thank you!

 

I'm guessing the intercooler doesn't like epoxy... I couldn't tell you for sure, but it's possible the intercooler is the problem.

 

finding vacuum leaks is a problem - you may need to go the next step and get a smoke test. You also may want to inspect your MAF and IAC valve and clean the throttle body. The other thing to do is check fuel pressure at the rail. You may have a problem with the fuel pressure regulator.

 

Check for leaks (intake or exhaust) between the MAF and the downstream O2 sensor. any leaks in that area won't agree with the expectation of the ECU. Also, try clearing the codes, performing a hard reset of the ECU, and see what comes back. That is N/A car advice, with the turbo, that may or may not apply. Your long term trims may be all out of whack, especially with boost thrown in.