2nd gen 420a help

[heyitseric333]

This is my first dsm and I'm a little frustrated so far. Just traded off my eg6 hatch for this 98 eclipse gs with a 420a 5 speed. At idle it almost sounds like it has a mild cam but then again it sounds like it's starving for fuel. I already checked the pump and changed the filter and I've already went through the ignition system and it's not misfiring at all. My next best guess is possibly the idle air control valve. It's not the throttle position sensor because it's not having trouble idling right. It hold steady and as soon as you give it some gas it runs fine. Just very lopey. Any feedback would be greatly appreciated.

 

[FalleN4ng31]

I would look at the IAC first, probe it with a multi-meter to ensure proper voltage at idle.

Also, any CEL's?

 

[heyitseric333]

Guy before me put a header and cheap n1 exhaust on it so both o2's are shattered but I checked for other cel's and the o2's were the only ones to pop up. But yeah I'll check the idle air control valve first. Thanks!

 

[Soto8]

Maybe you just have an exhaust leak? I know I have an exhaust leak and it sounds like it has a loop but it's just exhaust

 

[DJ Raydiate]

I would go ahead and replace the O2s as well. At least the one on the header. If the one on the header is bad the it is sending mixed signals to the computer giving it the wrong afr.

 

[PlanZero]

Second on exhaust leak. I have rough idle on my 420 after replacing tps and iac. Ran seafoam through the vacuum line and I got smoke coming out of the gasket and a cracked manifold. When I put it in neutral, the rough idle stops. Replacing manifold with headers ASAP.