OK my car was making 374hp 381 ft lbs with my TR224 cam, LTs. exhaust, cutout, lid, and MAF. A guy I know went in and messed around with timing a few months ago and all was fine. A few days back its kinda running rich and I decided to finally take it in and get it tuned. So I am getting it tuned and they do a baseline dyno......323hp, 350ftlbs.....WTF! Its running really rich...like 10.5-10.8 in some rpm ranges. They messed with it for three hours and got it to put down 336hp and 361ftlbs....still way off. They said that the non-stock MAF is causing this and I should get a stock one and they will try again. Everytime they change stuff around in the computer, it would get the A/F better, but then would go back to crap in higher rpms. At first the injectors went all the way up to 160% on one and 130% duty cyles on the other....but they got that down to both being 113%...this was at 6000+ rpms. It is still too high, but better than 160%. So can anything but a MAF cause this? In the beginning they said an O2 sensor might be bad, but ruled that out after they got em both to read the same. So any suggestions? Do you think going back to a stock MAF will cure this? I was hoping to get 380+ HP after a tune, but now I am hoping I can get it back to where it was before...

 

They say the MAF is good for 450-500hp stock, and not to mess with it. If you go aftermarket they usually make you lean out some. All I can say is grab a stock maf and try it.

 

I would upgrade the injectors to the 01-02 specs (28.8lbs). TSP has them for ~$60. You have 26.4lbs and are small. I would replace the MAF with a stock decsreened unit. I had a descreend MAF and it was difficult to tune with it. Put a stock MAF on and it was very stable.