Here's the issue with my 85...it's been happening for a couple months now:

Car starts fine whether hot or cold.
No apparent change in engine power.
Car WILL hold idle once warmed up.
Car will NOT hold idle when cold.

Intake manifold was removed and leaky hoses and vacuum lines replaced. Leaky intake sleeves also replaced, but the idle problem remains.

The throttle cable had been tightened right before this started happening, but loosening it didn't help.

Could it be something like a bad temperature sensor? What else?

Thanks in advance!

 

Aux. air valve/ idle air valve maybe?
engine temp sensor?
just some ideas. I think if the air valve gets gunked up it won't let the amount of air through that the engine needs when she's cold.