Hey All,
I have a 4.2 bottom and 3.9 plenum on my truck. When I am at idle the engine idle goes back and forth between 1800 and about 200. Low enough that the oil light comes on. I'm constantly working the gas pedal.
Several shops have not been able to diagnose so I'm floating it out here to see if anyone has any thoughts.

Thanks for any input.

Steve

 

What year?

 

Forgot that. 1993 110 NAS #472.
Cheers

 

Start with the dizzy, check the timing, vacuum advance etc.

 

What do you refer to by dizzy? I'm still new to this world.

 

The distributor, that is what they call it in the rest of the world and I dont know your location.
Replacing the cap and rotor would not be a bad idea either, but you must use OEM cap and rotor, after market does not fit well.