So im working on my 2007 Silverado with a 4.8 and ran into something interesting.

I put a 224/230 .553/.546 111+2 Cam, bolt ons, stall, various stuff in the last week.

What i found is when i cause the maf to fail by reversing the values in c0301 and c0302 (So i could dial in the V VE tables), the ecm completely ignored what seems like all the idle tables. It attempted to idle at 500 rpm with 28 degrees on timing. I did everything... changing the idle airflow, max idle area, and idle set points all over with no change in the way the engine tried to idle.

After a lot of searching i found a obscure post about a similar issue stating on some e38's... the ecm ignores the idle tables when a map/maf failure is detected. So.....

I put the maf settings back so it would not fail... and boom... it instantly idled and appears to respond to my changes in the idle tables.

So if i cant fail the MAF.... how am I supposed to log and tune in SD to get my VE dialed in?

I appreciate any help. TIA