1992 Corvette Runs Rough and Loss of Power over 3000 RPM

Von · 2007-04-07T20:15:58+00:00

All,I have a 1992 Corvette Vin P 350 automatic and it has me stumped.Nothing has changed on the way it runs and I have replaced thefollowing. New Opti Spark (TWICE) new GM Unit. New Coil, New Module,New Fuel Pump, New Injectors, New Plugs (Double Platinum) Factory, Newplug wires, removed and cleaned EGR works perfect, Checked compressionall at 190/200 PSI. Bought Snap-On Scan Tool and checked system. Oh,there were no codes and the check engine light was not on. With Snap-On Scanner I get a (28 QDM fault) Fan relay circuit. Strange sincethe Fan(s) both work perfectly as does the airconditioner. Other thanthat nothing shows to be throwing a code. Ohm checked the coil andnothing out of range. Replaced knock sensors. This does not have anESC box since it is a 1992. The ECM does ECS function. With the Snap-On code reader all readings are within normal and it says it is OK todrive. The timing, sensors, and such all read within normal range perthe Factory Service Manual Indications Page. The timing moves advanceand retard when the throttle is depressed. I am at a loss and want tocorrect the problem. The nice people at Vista Chevrolet refused towork on the car. I assume since it is a 1992 and ALDL they did notwant to take the time to diagnose the problem since it is not OBDIIwhere all you have to do is plug in and get a code. Oh, in park whenit reved it does rev up but slowly and in gear it stumbles over 3000RPM. It idles like it has a miss but was doing the same thing beforeI started.

Apr 07, 2007 25 Replies

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Empty3 19 years ago

Bill Heard... you are obviously in the Houston area. I would not trust that dealership.

Empty3

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Empty3 19 years ago

Call Chris over at Corvettes of Houston. He may be able to help you out.

Empty3

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Von 19 years ago

I am in Las Vegas and they have a Bill Heard here too. Give me the number of Corvettes of Houston and I will see what he has to say.

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'Key 19 years ago

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'Key 19 years ago

800-829-6434

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George 19 years ago

Here's one: Throttle Position Sensor

GeorgeC

92 Red/Red

V> Changed the fuel pump and filter and checked the pressure and it was

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