91 Celica, surging engine

I have a 1991 Celica GTS, 5SFE 5sp. I am fixing up. It has 287K, with about

110K on the motor.

The engine races usually at about 1800 RPM when I start to move in first, and also while I am driving in any gear, but the RPM doesn't really shoot up to much, just the forward motion. When I take my foot off the gas it calms down. It's almost like an uncontrolable turbo boost, lurching the car. When it happens I hear what could be a vacuum noise. I can't seem to find any obvious vacuum leaks.

Also, when I first start the car, the engine shoots up to 2,000 RPM, then back to 1000, if it's cold, it cycles like this a few time from +/-2,000 to

1,000 then comes out of it and idles just below 1,000.

Any suggestion on what component might cause this if there is a problem with vacuum somewhere?

Thanks for the help

-Andrew

Reply to
ADL
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A vacuum gauge will confirm the presence or absence of a vacuum leak. Sometimes the hoses get hard and crack or the vacuum fittings get brittle and crack. You can spray carb cleaner and see if engine rpm increases when you spray in a certain area.

Another possibility is a crack in the intake tube between the air cleaner and throttle body.

Reply to
Ray O

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