89 Corvette Runs Rough

1989 CHEVROLET CORVETTE
60,000 MILES • 2WD • MANUAL
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PHILMSHERMAN
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1989 Chevrolet Corvette Misfires after warmup
89 Corvette with 60,000 miles runs rough and misfires after it warms up. It starts good, idles and runs fine for about 5 - 10 minutes until it warms up. Recently had four fuel injectors replaced, new plugs & wires, new distributer cap & rotor. Fuel pressure checks out good. No check engine codes showing. What would malfunction on warmup? Could I have a faulty ECM?

Apr 28, 2011 at 3:34 AM
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MERLIN2021
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after ecm goes into closed loop the o2 sensors come online check them first
Apr 28, 2011 at 10:24 AM
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PHILMSHERMAN
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I disconnected the oxygen sensor and the car still ran rough after warming up. Check engine light did not come on.
May 1, 2011 at 10:09 AM
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MERLIN2021
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If the sensors are bad, unplugging it wont help, If the computer does not see a bad or disconnected O2 sensor, check the connectors to the computer, and the fuses, check cigar lighter, ecm and IGN fuses under the hood and inside the car.
May 1, 2011 at 1:22 PM
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PHILMSHERMAN
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I checked the fuses and then checked the computer codes again and found code 13, oxygen sensor circuit. There were no bad fuses. I then checked the voltage output from the O2 sensor after warmup and it varied from 0.1 to 0.2 volts with a varied engine RPM. Should I replace the O2 Sensor next?
May 3, 2011 at 4:06 PM
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MERLIN2021
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Probably the left O2 sensor drivers side, but it wouldnt hurt to change em all.
May 4, 2011 at 7:53 AM
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MERLIN2021
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If computr were bad you would have many codes, not just the exact code you got.
May 4, 2011 at 7:54 AM
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PHILMSHERMAN
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I replaced O2 Sensor, erased codes, then engine started and ran good until warmup then again started running rough and losing power. I checked codes again and no codes were set. What should I try next? Any ideas are much appreciated.
May 5, 2011 at 2:58 PM
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MERLIN2021
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you may need to check the coolant sensor. and maybe the wires in the O2 circuits
May 11, 2011 at 3:46 PM
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PHILMSHERMAN
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I took it back to a mechanic that had been referred by a friend and he rechecked the injectors. He found three more faulty injectors that had low ohm readings after warming up. I had him replace all of the old injectors and the Vette is running like new.
May 25, 2011 at 7:37 PM
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RIVERMIKERAT
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Thanks for letting us know the problem has been resolved.
Jun 25, 2011 at 9:54 PM
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