When it first started doing this, I thought it was the tranny going because it seemed to only do it in overdrive. While driving it today, I noticed that it was doing it in all gears. When I first get on the gas, it stumbles pretty bad. Once I get passed about a half inch of pedal, it accelerates normally. It also stumbles while cruising along around 1200-1600 rpm. Not sure if its a miss fire or a fuel issue. The opti is less than 6 months old and I just put in a new pcm and a new madz28 chip. Any ideas where to start?

 

Sounds like time for plugs and wires? Get it scanned for codes...

 

The cel is not on, but I'm planning on plugging in the scan tool tomorrow to check the o2s. I'm thinking they may be making it run rich causing the bog. Right now, the plan is wires, plugs, and fuel filter this weekend. Depending on what I find out tomorrow, maybe o2s also.