I have a 94 GMC Suburban 2500 7.4l....I think my IAC is failing. I have cleaned it and the bore, set idle by disabling the IAC. But when I start the truck, it will stumble then recover and stumble again, then recover. does this a couple of times. Once its warm, and I shift into gear, it will stumble then idle will go up and down between 200-1000rpm until I give it gas and go. Coming to a stop it will do the same thing. I looked up a new IAC motor and 2 are listed...a 10mm pintle and a 12mm pintle. The one that's in the TBI now has been replaced before...my question is.... HOW DO I KNOW I HAVE THE CORRECT ONE?..
sorry, wasn't yelling, just wanted my question to stand out.
Thank you for any advice.