Please Help! P0171 & P0174

carnut96gt

hey bud,, if you find out your problem pm me.. i have the same probs,, and a local shop tech checkd and i have NO vac leaks... i do have cai /and slp x pipe,, he said it was the fact that ther is more air in, and mostly alot of air out the high flow slp cats, not 6 cats oem. had to dyno/chip the pc for the new flows in/out.

If you want to check for vacuum leaks, just buy a vacuum gauge, there pretty cheap, under $20

I'm also leaning towards a vacuum leak. I just helped a co-worker with the same problem on his 98 Taurus. It was a bitch to track down. The vacuum leak was a molded vacuum line tucked under the throttle body. He had to go back to Ford for the piece. Good luck man. Pearl02.