Just did a header, water pump, opti, plugs an wires install. I probably drove the car about 100 miles already without any problems, an today i was out, an i hit the rev limiter once, an then a few mins after that it was mis firing...

I can put it in drive an it kinda shakes n stumbles. It starts goods, an idles kinda funny but hard to notice it.

Any idea what happended?

 

Burned a wire on the headers?

Before you installed the Opti, did you check the rotor screws and lock-tight them? Was it a GM Opti, or some other brand?

 

Where the headers coated? Check to be sure the plugs aren't loose, the wires aren't burnt or loose and the water pump isn't leaking. With several thing all at once done it could be a couple of things.

 

could also have a cracked plug like i did!!! just take your time and double check everything..

 

Yes it was a GM opti. And no i did not check the screws? I did not know i was supposed too...