Mitsubishi Repair: 95 mitsu runnning bad when warm, mitsubishi eclipse, cam sensor

Question
I have a 95 mitsubishi eclipse (GS).  It has been through the ringer recently.  The newest problem that it has is having problems running when the engine is warmed up.  It runs fine for about 10-15 minutes, then the RPMs start to fall every time you press on the gas and it starts to jolt while the rpm needle goes crazy, this  also happens when it is in gear.  It does not ever actually stall.  If idling in neutral it seems to do fine (although lately that isn't a sure thing either as the problem seems to be getting worse).  I replaced the cam sensor, and it didn't fix anything.  Tried hooking up a scan tool and it won't connect to the ECU for some reason.  The ECU is only about three years old.  Any ideas where I can start trouble shooting?  Oh and I tried reading the check engine codes but I don't have an exact chart match for this car so I'm just guessing.  Thanks for your help.

Answer
Trevor,
Your most likely dealing with a bad component that handles idling.  The idle air controller (IAC, sometime called the idle speed controller) manages the appropriate idle speed after the engine is warm.  If the IAC is faulty, the car's computer will not be able to regulate the idle properly, and you'll get the "idle surge" symptoms you're describing.  You can also check you base idle set screw (BISS).  This BISS is located on top of the throttle body.  It allows a measured amount of air into the engine when the throttle plate is closed.  Over time the rubber o-ring with rack and allow air to leak out.  This also causes idling issues.  I had this happen, and in my case the o-ring failed completely after about 5 years of progressively worsening idle issue until the screw itself popped out completely.  

If all else fails, and can use a timing light, you should check to make sure the timing belt is properly adjusted.  If the belt is stretched, it can cause improper tension on the belt and ultimately a failure.  Have the checked if you have not replaced the belt or tensioner in the last 60k miles.
Good luck!