I just put my heads back on my car and I'm getting a bad stumble. Mostly in the lower rpm range. It never did this before the heads were ported. I hooked up a tech 2 to the car and everthing looks normal to me. There were no misfire codes. What should I be looking for? If there are no misfire codes, does this mean it could be fuel related. Like I said, this was not a problem before I took the heads off and had them ported and put them back on. Any ideas?

 

Possibly a vacuum leak around the intake: between the manifold and heads or the fuel-injector o-rings.

How much more flow are you getting with the ported heads? A lean condition caused by the increased air flow or bad fuel pump will cause a stumble.

 

I don't think it's a lean condition. It is kinda running rich. Mabe a leaky injector or something? What kills me is that it was running perfect before the project, so, it's gotta' be somethin' I did. Anyone ?

 

Does your PCM reprograming include the porting??

It does sound like a vaccum leak. You could also have incomplete combustion, which would look like a lean condition.

Is everything hooked up?? It may be possible you missed a conector, not saying you did, but it can happen.

 

I've checked to see if everthing is hooked up. It is programmed for the new heads.