Hey everyone so a month ago I replaced my intake manifold and at the same time i did all my ignition coils. Everything has been good until today my truck started running rough like it was misfiring again and I'm not sure why it would be I've done my plugs and coils why would it be misfiring could it be a bad fuel injector or what.

 

Might be an injector. Wait for it to pull a code so you know what plug to look at. Do you have a check engine light? If so, post the codes.

Or you can just start with cheap, usual and easy stuff and see if it helps. Clean the MAF and throttle body, replace fuel filter, replace FPDM, etc..

 

Yea the check engine light is on now but I have to wait for Monday for the mechanic too look at it To check the code

 

I did my plugs at 100,000 I now have 118,000 and after that I had 2 separate misfires and I decide to change out all the COPS. It ran fine for a few months and now yesterday it misfired again. I'm not sure which cylinder or what code it's throwing because I have to wait till tomorrow for my mechanic to check it. I'm so frustrated because when it misfired the first time it fried my one cat so that's why I replaced all of the COPS and had the cat replaced after and now it's doing it again. The only thing I didn't do was replace the spark plug in the cylinder that misfired I'm not sure if that makes a difference.

 

could be the other cat now...driving with a sever misfire will cause your cats to get clogged...you can have your codes pulled for free at most local auto parts stores now days.