Eclipse running rich

I have a 1991 Eclipse Gs 2.0 non turbo, that runs rich and has erradic idle, when it gets hot. I have replaced O2 sensor, put new exhaust on, and even a new throttle body on. I am thinking that it is the ISC, but I don't know how to check it. If anybody has any ideas, plz Email me I don't want to run out and buy a $200 dollar part if I don't have to.

Sounds like maybe your FPR(Fuel Pressure Regulator) is clogged or the vac. line is unplugged... thats the running rich part.

Idle surge can be caused by a BUNCH of things.... mis-adjusted BISS , bad ISC , FIAV is out of spec , you have vacuum leaks...etc.
I have a '90 Galant with the 2.0 myself , that was having this same problem...

If you need some in-depth advise..PM me and I can point you in several directions.....:cool: