Quote:
Originally Posted by mrg666
I have not seen P0172 because of bypass valve. P0172 means fuel mixture is too rich in other words not enough air. When the bypass valve is not working when the throttle is closed, it just stays closed and causes P0174, lean mixture (not rich) due to too much air at idle (and, of course, the risk of compressor surge). If bypass valve working okay, you should be able to hear the whistle of bypass valve opening with closed throttle. It is also useful to have an OBDII reader to check the MAF value. It should be stable around 2.8-3 at closed throttle and warm idle if MAF sensor is working right and bypass valve is opening.
If you have P0172, fluctuating rpm at idle, and hesitation before revving up, I would clean the MAF sensor first. If it doesn't help, i would check the leaks from air pipes and vacuum hoses.
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Thanks for that. Just cleaned my MAF this afternoon, cleared my codes and, things seem to be working correctly again. I did check the evap hoses under the intake manifold and, while the are movable on their spigots, they had not come off to date and I've had the JRSC for about 1,200 miles or so. I'm still going to secure them for piece of mind, but haven't made it a high priority.
Also, I was thinking maybe it was the bypass valve because of this
https://www.ft86club.com/forums/show...01#post3088309