I know this is a group for Chevy trucks but I can't seem to find an answer anywhere for this problem. I just rebuilt a 3.1L Pontiac Grand Am motor , auto trans, and it idles great, but when I take it up to 55 it starts to shutter until I let off or stomp on the gas, I read two codes, MAP voltage too low and IAC inproper setting, I changed the MAP no luck, I don't have any vacuum leaks and at idle a vacuum test shows no probs, any ideas? TIA
- posted
19 years ago