vanster

Upon another trip from the Bay Area to LA and back my '80 has developed a random idle pattern. It will run up to 1500 then back down to around 800 after a few minutes from a cold start. Then it seems to settle in around 1200 -1500 or so once warm

Is this a sensor issue?

Speedtoys

Have you tried a new weatherpack connector?

vanster

I thought that was a joke
Yes, I clean and inspect it often

vanster

Seriously...is it the 14 pin?
I can't seem to get the idle to drop below 1200 and upon start up it will ocillate from 600 to 1500

James Bailey

1980 the auxiliary air valve sets the high cold idle then gradually closes down the bypass as it warms up. It has a spiral spring inside which gets heated by an electrical current. It moves rather slowly.
If it will not idle down when hot and oscillates I would suspect an air leak.....unmetered air like from a split intake runner boot. That would lean out the mixture making it run poorly cold and letting it idle too high.

Speedtoys

Was a joke based on a hot thread at the time..about fancy 14pin replacements and their benefits...other than being a better plug.

vanster

thanks
Sounds like an intake refresh in order. I have been driving this car 1000 miles a week, all highway from SF to LA and back.

PorKen

Possibly worn out vacuum limiter (flying saucer shaped thing on the side of the throttle body).

vanster

Thanks. I will check it out

vanster

I replaced the vacuum limiter and I still have a random idle at start then a high idle from then on.
If I run the engine for 5 hours straight it still stays up. A bit better in warmer temps like LA mid 80's it will drop about 100 revs.
Is this a vacuum leak?