99 Mystique 2.5 chugging and rough idle

[GreenMyst66]

Hey guys, my cars been chugging real bad or rough idling, but never dies. and most of the time it's fine. I know the imrc is bad, and it's got a new idle control valve. I'm thinking something bad in the fuel system maybe? Thanks in advance

 

[satya_svt98]

spark plugs and wires first....

 

[projectSHO89]

My 2000 2.5 was doing much the same thing during the single digit cold snap earlier this month. I've definitively diagnosed it to an intake manifold leak caused by dissimilar rates of shrinkage with 15 year old intake gaskets. It's since warmed back up with lows only into the 20s and the problem has gone away for the time being. I'll replace the gaskets once it warms up some more and I have both free time and some extra daylight.

You'd need to provide more details about your condition for a better idea of what's going on. The IMRC won't cause your issue but an IAC might. A weak fuel pump, restricted fuel flow, and a bunch of other things can also cause your symptoms. If you can check the long term fuel trims and see if they're skewed heavily in one direction or another.

 

[GreenMyst66]

Since I bought it I havent gone through the fuel system yet, but I have changed the IAC and the intake gaskets. fuel pump and filter were next on the list to change