i just bought my first vehicle.. a 1989 ford bronco with a rebuilt 302 v8 that is less than 2 years old.. it runs strong.. however.. when i am at a stop light and the car is ideling the rpms slowly bounce up and down between 500 to about 800-850. what would cause the eradic ideling on it?[img]/ubbthreads/images/graemlins/confused.gif[/img]
Try a coolant temp. sensor. Located by the thermostat housing if I remember right. Or possibly just your Idle Air control(IAC) is a little dirty and sticking. I go through coolant temp. sensors quite a bit. Produces the same problem.
first off never start replacing sensors on an efi controlled system with out scanning for codes first. you can spend lots of money chasing a ghost if you dont. your haynes manual and www.fordfuelinjection.com show you how to pull codes using a paperclip. that symptom you discrib is usually the TPS but still scan codes