Hello I just joined so please bear with me...I have a 1993 eclipse gs non/turbo when I bought this it had all sorts of parts in the hatch but I thought I would get it anyway (good price) I took the head off to find the timing belt had broke along with two valves which were sticking in the pistons so instead of re-building I bought another engine and installed it....now the reason the parts were in the back is starting to make since (problem) The car idles like it is supposed to around 900 rpm while warming up after running for a little while it starts to surge between 700 and 900 rpm until you turn on the headlights or the a/c then the idle drops down to 500 - 600 rpm still surging and starts to shake since is so low on top of that the oil pressure goes way down, plus the butterfly sticks occasionally... I replaced the egr last night thinking that would do it I pulled the ISC and replaced it with a used one still the same problem I don't know what to do I put a k&n cold air intake kit on it and that only made it worse now the darn thing started dying when I drive on the highway and push in on the clutch to down shift or if I rev to 5,000 rpm it started a clatter noise almost like lifters

 

ok update to my problem I bought a brand new IAC valve from the parts store installed it helped but did not solve the problem now it just goes hay wire every now and then some times it idles awesome then at other times it idles around 1400 rpm other times the idle jumps from 400 (almost dying ) to 900 rpm I'm at whits end plz help is it my comp. or can be it be my maf????