What to check for erratic fluctuating idle

[Lou and Blue]

Once warmed up, my '85 GT 2.8 v6 idles from normal to very low and the oil pressure drops into the red. Up and down, up and down she goes.
I've been advised to clean and replace the IAC and also to add grounds to the block.
Any advice? Other than to go fuck off. LOL
Thanks guys.
Louis

[Aaron]

Good attitude, those sound like good places to start in my opinion.

[CincinnatiFiero]

Check for brittle or cracked vacuum connectors. My 2.8 was riddled with them.

If its really bad the EGR supply tube cracks and can cause a big vacuum leak.

[The Dark Side of Will]

Checking a Fiero for vacuum leaks is always a good idea.

However, vacuum leaks result in a high idle, as the engine is getting lots of air, even with the IAC fully closed.

IAC is the most common cause of low or fluctuating idle... but you could have the idle air passages in your throttle plugged with carbon or similar trash as well.

[CincinnatiFiero]

On my car I just removed the throttle body, removed the iac, and soaked the iac in throttle body ckeaner while i cleaned the entire throttle body as thoroughly as I could.

[Shaun41178(2)]

Fluctuating idle usually isn't caused by a vacuum leak. Usually a high idle is that symptom. I say take off the tb and clean it and clean the iac valve as well. I am guessing its linked up from the pcv and egr over the years

[Lou and Blue]

Thanks guys! I figured I'd get a whole lot of good advice here. I will clean both the TB and the IAC. That is, if this snow ever melts!