Hi everyone I just had 2 catco catalytic converters put on my car seeing as the old ones were rattling. I have not been using the car a lot but now I want to start using it since the summer is here. Anyways I am not sure if its the cats or maybe something else but seems my cars idle is rough now. When I am at a light I feel it. I also just installed 2 K&N filters and an accel coil.

Today I took the cap off to check it cleaned it and its fine. I changed the plugs on the car about 12k miles (3 years ago) ago and wires so I don't think its that. I also just cheked the engines timing and its on the money.

Anyone have any other thoughts on what I can check? I am getting no codes either.

 

Do a cylinder drop test.

Get running and warm, disconnect IAC, and one-by-one disconnect injectors until you notice a cylinder that doesn't make much difference, if any. That'll be the weak cylinder. Then you have to figure out why. Might have more than one.