Hey guys i got a 2001 ssei,its idling rough but as soon as u hit the gas its good it dosnt seem to have a power loss but it got worse since i bought it,just at idle tho.knock sensor? tps sensor?,oxygen sensor?,i dunno it did it before the 3 in exhaust and still now after any input would be appreciated

do you have an engine light on? if so take it to autozone and get us the code(*) and we can help you out a lot better

no engine light is on thats why im kinda stumped

You put a 3" exhaust in? maybe at idle its losing too much backpressure, or something else clogged up

I'm leaning towards a vacuum leak or an 02 sensor, seeing that you replaced the cat also.

I'll go with vacuum leak. The EGR tube would be my guess.

thanks guys i will make sure to replace the egr and look over it real good for leaks,because im going to be doing some mods so i wanna make sure everything is good before i do anything else,i will try that and see

Whoa don't go wasting money on the EGR, we can't see your car so you need to check it or have it checked by someone

the reason i said i would just replace it is because i was told by two other people when i described how it was running they said an egr valve or a vacuum leak because of no engine light is there anything else that could make the engine run like that only at idle without setting off a light.

Check all the vacuum lines and the EGR tube by spraying carb cleaner on all the lines. If the RPM changes, you found the leak.