[knomadd]

Since you're talking about it, and I had a different but slightly similar issue when I first got my swap running, I'll throw this out there for you.

My STFT (short term fuel trims) were WAY off. I mean WAY WAY WAY off. They stored a 30-34 through all cells of my LTFT just to get my STFT in the 24-28 range. This is showing a severely lean condition. BUT... It smelled super rich. All things pointed to a vacuum leak, a bad connection to the O2 sensors, bad O2 sensors, or a bad MAF (although I could only fine one reference to a MAF sensor issue).

I replaced the MAF and had no change. Cleaned the old one and again, no change. Couldn't find a vacuum leak anywhere either.

So, I talked with my tuner, told him I had a larger intake (3.5" tube) than the van the motor came from, and wondered if he could play with the MAF tables to get it working. His first attemt was to bump it by 20% (so he told me) and it changed, but still in the low 20s for STFTs. 4 more revised tunes and I'm now at a LTFT of -3 to +4 (most at 0 to +1) and STFT of -4 to +11, most at about -3 or +5, depending on load.

All of my research said if you have fuel trims beyond a +/- 15, there are some major issues. Now, that's not to say you can't drive it, but the longevity of the engine would be compromised, however slightly. Talking with a local hotrod shop, they told me as long as I had my STFT in the high teens or low 20s I'd be okay for a short period, but definitely get it checked out before your first oil change.

I say all of this because you may very well have a tuning issue where the intake is allowing more air into the engine than the MAF can register due to the parameters in the tune. You may just need a good tuner to make some adjustments to the MAF tables and it COULD fix your issues.

Good luck!