Hello,

I have a Buick Century with the 3.1 3100 engine it has been a great car so far has 203k miles, had recent tuneup, new ac delco plugs, wires, new egr valve, the problem I am having is if you are sitting at a light for example and it misses while idleing but, wont miss if I give it a bit more gas it smoothes out, no check engine light or codes showing up and ideas what it could be I had to clean out that port that runs to the egr it was clogged up with carbon, and I also clenaed the throttle body as well, any help appreciated!

Jim

 

Welcome to the forum! You can try checking for vacuum leaks. Also, when was the fuel filter replaced last?

 

Might be a good idea to recheck the EGR valves. A piece of carbon could have become lodged under one of the pintles preventing it from completely closing. Usually any unwanted EGR flow at idle will cause a rough idle and disappear with increased throttle opening. Also make sure the IAC ( Idle Air Control) valve doesn't have some accumulated carbon in it's passage