3K idle and wouldn't go down, what's going on?

[Zola]

Driving yesterday in California it was a hot 90F+ day. My '76 FI drove fine for grocery run. On way home, out of the blue, she stalled at stoplight. Did a very hard start with gas pedal mashed to floor, finally started up and she never idled below 3K from then on, I looked down and oil temp. gauge was dead...Drove about 5-10 more minutes to get home...After letting things cool down, hours later I went out to start and idle still very high 2.5K to 3K and won't come down....oil gauge is working again...WTF is going on?

[Zuffenwerker]

Throttle linkage hanging up on something?

Daniel

[tonythetarga]

Sounds like a vacuum leak. Check the hoses.

[Dave at Pelican Parts]

Two main things could cause a high idle.
1 - more air going into the intake
2 - ignition timing over-advanced

For 2, check your timing. Dig out a timing light and our Tech Article on the procedure and have at it.

For 1, the first thing to do is look for hoses that have fallen off. This seems like the most likely cause of a very sudden air leak. Next, try moving the throttle valve and see if it does close smoothly.

--DD