1998 Saturn SL2 98 saturn sl2 idles fast in gear

1998 SATURN SL2
80,000 MILES • 6 CYL • 2WD • AUTOMATIC
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SZBERT
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My 1998 Saturn SL2 idles fast in gear when it warms up. The temp guage never goes above 1/4. I've replaced the ECT sensor with a part from Autozone. I've done that twice. Local mechanic said only the factory ECTS should be used. Local mechanic replaced IAC valve and cleaned intake throttle body and flushed injectors. I still have the same problem. Also have a misfire in cylinder 4 (P304 code) Have replaced spark wires and plugs. Still have miss. When warmed up the idle goes as high as 3,000 when I change from D to N. Then it slows down to a rough 700-800 RPM in neutral. As soon as I put it in gear the engine races and I have to hold hard on the brakes to keep the car from moving. If I put it back into Neutral, the RPMs come down after a few seconds.

I'm stuck. Where do I go from here? I can't afford a trip to the dealer. I already "wasted" $600 to have the IAC replaced and it didn't fix anything.
Jan 29, 2010 at 10:03 PM
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DOCFIXIT
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Hi
Was compression tested? was injector tested for proper fuel delivery? What is engine temp in degrees warmed?
Let me know
Thanks for donate
Jan 30, 2010 at 1:00 PM
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SZBERT
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Compression tested the same in all cylinders and all the injectors were tested "OK"
I don't know how to check actual temp in degrees. my simple scan meter doesn't report that.
Feb 1, 2010 at 5:47 PM
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DOCFIXIT
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When engine is started cold is there coolant flow in radiator? if yes then replace thermostat
Feb 2, 2010 at 8:57 AM
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SZBERT
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The thermostat wasn't stuck up, but I replaced it anyway since I had one, and flushed the system. Still, the same problem. Fast idling in gear, and the dash temp sensor never rises above 1/4.
Feb 4, 2010 at 7:55 AM
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DOCFIXIT
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The in gear rev up can't think what would cause this but IAC pentil opening. Try this disconnect IAC see if rpms go up in gear
Feb 4, 2010 at 11:05 AM