I have a 93 vortec (4.3) that has a fluxuating idle when sitting. I did wires and plugs but didnt help. any ideas?

I have a 93 vortec (4.3) that has a fluxuating idle when sitting. I did wires and plugs but didnt help. any ideas?

On my 93 vortec (4.3), a fluctuating idle was one symptom of a bad cpi. I had a very rich mixture which overwhelmed the computers ability to control the idle. It could also be a sticking IAC (Idle Air Control) valve or an EGR valve stuck open because of a piece of carbon. Usually, when my EGR was stuck open, there was also serious power loss at low speeds and I had to give it some throttle to keep it idleing or the engine would conk out.

thanks for the advice, I havent had a chance to check it out yet but will let you know my findings.

check the mas airflow sensor or the egr valve blazers are big on the egr valve maybe theres lots of carbon buildup let me know what yougot
blazin911

need to do more than plugs and wires.

Cap and rotor, PCV valve, fuel filter, TB cleaning etc....