P0171 help

[fomas1]

Can the lim gasket be the cause of a vac leak? I justed replaced my lim gasket and i have a vac leak, dont see how the lim can be the cause ofavac leak thou.

[wstefan20]

Well the pcv runs through there if I can remember... but I doubt it. I had the same issue after replacing lim gasket, and it ended up being the rear o-ring on the upper intake manifold going to the brake booster. Though you'd probably have symptoms with the brakes like I did... Though there is a t-off on top of that that goes to hvac controls that is very fragile and tends to leak/come off. Can't think of anything else vacuum related you would have touched other than the throttle body itself or the upper intake manifold. What other symptoms do you have?

[fomas1]

The pvc vavle o ring wasnt seated right(fixed running better but still not right) running rough and getting the p0171 aswell as c0236,c0035.I did spray around everywhere did get any hits.

[FordMan77]

Did you remove the EGR pipe and inspect it for cracks, especially around where it bolts to the LIM and EGR? It likes to crack there and won't be picked up on the brake clean spray test. The only other things that come to mind is a warped UIM, or possibly an injector not seated correctly.

[wstefan20]

Hm... the two other codes you mentioned are possibly the wiring, the abs module, or the speed sensors. Same happened to me. I was able to read the abs data and found one sensor was jumping all over the place. Replaced hub assembly, no change. Replaced wiring, no change. Took apart back of abs and also inspected connectors, seal leaking and corrosion all over. Had to replace and have dealer re- program.

Have you checked fuel pressure? Bad regulator is common and threw codes like this for me. I would also grab a can of maf sensor cleaner. Stuff works wonders. If you decide to replace sensor, go for cheap one off ebay. Has worked for me for several thousand miles.

[fomas1]

thks everyone still chasing it