[jwvand02]

So I put the car back to stock in order to sell it. It popped a P0174 code, and so I went to investigate. This has been a long running issue with the car, but thought it was solved. It has an aftermarket header that I have long suspected to be the culprit, which I found a crack in at one point but had it fixed.

The behavior it's exhibiting now - LTFT is extremely high, 20-22% but only under no or very little throttle. Any throttle and LTFT goes to 0. STFT are within 1-2% under all conditions. I checked under the car, and lo and behold I found a nut missing from the header that I guess I didn't torque properly at some point. I fixed that problem, and assume that is the cause. I pulled the positive battery cable for about an hour under the assumption that it would reset the fuel trims.

There's no obvious sign of misfire or knock, the car doesn't appear to be pulling timing. My next thing to do is just to put the stock header back on.

I guess I have two questions:
1. Is it possible that the fuel trims didn't reset and that the LTFT will come down over time?

2. Am I barking up the wrong tree chasing after the header? I don't really hear any signs of an exhaust leak, but I'm close to positive there's no vacuum leak because I was extremely careful when assembling the intake.