Been trying to track down a problem for awhile now and may have an idea of what it is. The tune is straight, one that I ran for a long time with no problems before. Can some of the experts take a look and give me an opinion to what you think it is? Note the idle fuel trims...

 

It is fueling below 4500 hz on the MAF (worse at 3500 and below), why I don't know...if nothing has changed and there is no vaccum leaks, the maf is clean etc.. Try this, 3500 hz and below add 11%, 3500 to 4000 hz add 5%, from 4000 to 4500 hz add 2.5%. Log that and see what it looks like.

 

The Frequency values that you mentioned are definatly off by alot.. Im just curious as to why any value below 4000 Hz is so far out..?

 

That is the million dollar question! If all looks good mechanically and physically with the intake setup then I don't know? I get a lot of people that have weird *** maf readings when they come for a tune, f bodies especially....

 

I have read about F bodies having MAF problems... I think I might switch out my MAF with my friends and log to see if anything changes. If it does that may be the million $ answer

 

Ok, so for the hell of it I went down and got a can of MAF cleaner and sprayed down my MAF real well, let it dry and tried it out.. Nothing was changed in the tune. Here was my results

Note around 20% throttle at around 1300-1400 rpm in Park I get some popping. Sounds kinda like 2 step. I tried to catch it on the log near the end...

 

Take 8* of timing out and try again. Thats a holy moly amount of timing!

 

As in I wouldn't push more than 50* even in the lightest loads and lowest of rpms. Id stay around 48 or so for this application, for the highest point on the table then blend that in with your higher load settings.

 

Interesting.. I thought it was a tad bit high but when I compared mine to the stock timing table I was only 2-3* higher in those areas...

 

Interesting, I had a stock file that was like 45* in that area..lol I would try lowering the timing some, it may just be too far advanced.