94 LT1 missing at idle - LS1LT1 Forum : LT1, LS1, Camaro, Firebird, Trans Am, Engine Tech Forums

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post #1 of 5 (permalink) Old 11-27-2012, 11:05 AM Thread Starter
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94 LT1 missing at idle

New to the forum and just bought my first LT1 in a 94 Camarao z-28 convert. I have been working on and rebuilding all gens of camaros for 20 years now and im at a loss for my issue. The car has 105k on miles. The car was running when i got it but it needed work. I replaced the orginal water pump , opti, wires, and plugs with all AC delco parts. I took out the injectors and flowtested them and cleaned them. While i was flowtesting them i found one that was different and was flowing half as much as the other ones. I think this may be part of my problem. The problem ,which im sure has been covered but have not found on here yet, is that when i start the car wether it is cold or hot , will have a miss at idle and can still feel it slightly as i increase my speed. IT is not backfiring nor is it dying on me . The idle is at 500RPM when it is warm and my fuel pressure is with in the specs it is suppose to be. It has a stock LT1 with the TB bypass mod cold air intake and a flowmaster muffler and new cat from what i can see.

So im thinking of replacing the injectors and the O2 sensors. I have rechecked all my wires and plugs. Im at a loss as what to check for getting rid of the miss i have PLEASE HELP i dont want my first LT1 to be a bad experence Thanks Steve
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post #2 of 5 (permalink) Old 11-27-2012, 11:24 AM
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Positive all wires are on correct location? O2 sensors and dirty MAF can also cause similar conditions. Also, make sure all your grounds are good and clean.

1995 TA: Converted Nose...381 LT1...4L80E...12 bolt...3.90 Gears...4000 TC
Best 1/4 10.71@ 125.73, 1.46 60ft, 3450lbs.
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post #3 of 5 (permalink) Old 11-27-2012, 01:16 PM
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O2s wouldnt cause a rough idle condition on cold start though, would they

has to be something active in open loop
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post #4 of 5 (permalink) Old 11-27-2012, 04:01 PM
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Not just grounds, but check wiring, connectors also. Have you checked the opti wire harness that runs between opti and passenger side of intake. Check it's wiring and the connectors for burnt, bent, corroded pins.

Spray a little mist of water on spark plug wires, run at night, and see if there is any spark leakage. Do the old pull a spark plug wire off, while running and see if it changes the rpm. Do all 8.
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post #5 of 5 (permalink) Old 11-27-2012, 07:01 PM Thread Starter
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When i did the new opti i also got it with a new connection wire harness. I double check all the grounds, had to deal with that in my old honda, i do plan on replacing the O2 sensors and injectors in the near future. Im just making sure that i covered everything else.
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