I did a de-k motor swap recently and ever since i got the motor ive noticed it idled a bit rough but still drivable, it doesnt make any funny noises.. rod knock etc... However i cannot figure out why its misfiring, ive checked the coils and they seem to be ok. Im thinking maybe i have a cracked head on a fuel injector but im not sure. Yet i dont get any codes for the misfire so i dont know what to do. If anyone has any ideas id appreciate the help

 

How can you describe the misfire that you get ? How it feels like ? You said the only thing you notice is that it idles a bit rough, did you replace spark plugs ?

 

I believe it misfires a bit sometimes when im driving but at idle i can feel the motor misfiring(it shudders) and i can see that it is shaking alot, and i know its not supposed to be like that. I have ngk platinums with about 10k on them probably less. They last for about 60k.

 

Take the spark plugs out and inspect them; one of them may be damaged due to a detonation or fouling even while they are new.
Did you replace fuel filter ?

 

Is it just me or does it seem that every time someone has a problem with idling/misfiring the first thing they do is replace coils, and that NEVER solves the problem?

 

LOL yeah coils and injectors and the problem is still there.

 

well ive checked all the coils, and they all test OK. The reason i think its the injectors is because i had to jb weld lower im of the dek manifold to close up all the holes where the butterfly valve rod used to be. So when i was sanding the jb weld down im thinking the sand may have gotten into the injectors.