95 sunfire Computer problem

[lashaiec]

Hi,
My brother owns a 95 sunfire. Recently it began idling rough, sort of cycling high to low while idling in park or at stop lights. at other speeds the car runs fine. I figured o2 sensor and changed it but it didn't help. We took the car to a local mechanic and he did a scan. Codes for both the o2 sensor (wich had been replaced) and the MAP sensor were coming up. We changed the MAP, and the car still behaved in the same way. The car went back to the mechanic (I wasn't there this time). My brother told me the mechanic scanned it again and the same codes were back. The car does drive ok from time to time, but the problem is always present. Mechanic said he thinks it's a problem with the computer. Says we should get a new one. Anyone here have better (cheaper lol) advice for me? is it worth it to trace out the wires from the o2 and MAP to the computer to check for faults ? or should I do what the mechanic said and scrap the computer for a new one? the car is a 2.2L and has about 240,000km on it. Thanks in advance for any assistance.

[hren]

Originally Posted by lashaiec

Hi,
My brother owns a 95 sunfire. Recently it began idling rough, sort of cycling high to low while idling in park or at stop lights. at other speeds the car runs fine. I figured o2 sensor and changed it but it didn't help. We took the car to a local mechanic and he did a scan. Codes for both the o2 sensor (wich had been replaced) and the MAP sensor were coming up. We changed the MAP, and the car still behaved in the same way. The car went back to the mechanic (I wasn't there this time). My brother told me the mechanic scanned it again and the same codes were back. The car does drive ok from time to time, but the problem is always present. Mechanic said he thinks it's a problem with the computer. Says we should get a new one. Anyone here have better (cheaper lol) advice for me? is it worth it to trace out the wires from the o2 and MAP to the computer to check for faults ? or should I do what the mechanic said and scrap the computer for a new one? the car is a 2.2L and has about 240,000km on it. Thanks in advance for any assistance.

If it's shacking rough there could be a couple reasons for it.
- Computer
- Fuel Pump
- check if Valve is sticking
If it's fuel pump - it would happen when u move as well... so I doubt it.
Computer - there is no need in new computer - they are trying to rip you off - just re-program it - much cheaper.
Tap on the Valve and see if it runs smoother - if so, bad EGR. Check plug wires.

[hotbug1776]

you cant reprogram the 95 computer, at least on the 2.2L auto/manual and the 2.3L manual. they both have removable chips that are burned. not like the 96 and up which can be flashed and reprogrammed since the chip is soldered in. make sure the case isn't leaking on the computer, it was a problem for the 95's I got my stock computer sitting in front of me, it's a paperweight now due to it leaking. I got a 2.2L ATX chip around here somewhere that came with my current computer. If all your sensors read bad even after you test them and determine thay are good, then it's a faulty computer.