Hey guys !
I am at wits end with this truck. I'm working on a 2003 Silverado SS and I have built a 408 stroker for it and ever since I installed it is have had it sputtering and miss firing between 2700 and 3800 rpm. It is not a tuning issue nor is it a vacuum leak. All the plugs look the same when I pull them and all the coils are brand new. I have 2 small grounds on the back of the engine + the body strap, and one small ground on the front. New cam sensor , new battery , new alternator , new spark plug wires. The only code I am getting is a P0101 ( mass air flow out of range ) , I also have an ls7 maf and the proper tune for it. The truck also runs worse when I have any electrical load on it (heat, air, electric fans, ect). Any ideas or insight would be much appreciated!

 

If anyone has any other questions please ask!

 

Dont rule out a tuning issue.

Do you have hptuners or efilive where you can post a log file? That would be most helpful.

Right off the bat try the stock MAF with a stock MAF curve in there to see if it gets you close.

 

Using efi live and I don't have a file I can post unfortunatly. I have tried different ls7 mafs but not the stock one, seemed like a lot of trouble for something that may not work

 

I have a feeling thats the source of your problem. If this is a NA setup the stock MAF will be more than enough anyway.

 

Do you know off hand if an ls7 maf is the same as an ls3? Might be my issue right there

 

I dont know off hand

 

I'm wondering now too if my MAF sensor is maybe too close to the filter and is picking up turbulence, sounds like I have a few things to try this weekend

 

Well I moved my sensor farther down the tube , bought a new maf too and still no luck .. I don't have the ability to re-tune at the moment so I can't try the stock maf. I'm wondering if there is a grounding issue still ...