Bad Idle

[Keatonc]

So after I switched out engines on my MP3, the new engine seems to have a bad idle. Only when I first start the car, and when I come to a stop, the engine almost stalls and then forces itself back up. What could this possibly be? All that I have done is installed an OBX header (which doesnt fully connect to the tailpipe). But there is no lag or issue when I am driving (in or out of gear).

 

[tweety2300]

Egr valve

 

[Keatonc]

I fixed what I thought was the issue. Its been a couple weeks and the issue is still present. I have OBX headers and connected it to the egr valve poorly. I fixed it by wrapping the small crack in the connection with heat resistant exhaust wrap. It runs alot better, but after about 10 seconds off of the throttle, it skips and goes back to normal quickly. This only happens when the engine has warmed up though.

 

[rae rae]

coils
60-8- bucks and it takes 5 mins

 

[Keatonc]

coils
60-8- bucks and it takes 5 mins

I just replaced them. Same issue unless they need to be worn in. Could it be sparkplugs?