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3.4 DOHC problem


96montecarloz31
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Picked up a 94 Cutlass SL with a 3.4 in it to play around with. prior to me buying it we had swapped in the 96+ intakes and throttle arm. The timing belt, plugs, wires, gaskets from heads up, ect. have been done. The problem I'm experiencing is it will run fine when cold, but once warmed up it acts like it has a miss. It bogs down majorly (basically no accel) and starts to shift very hard. I had put in 96+ injectors but swapped back to the 94s because of an idle problem (seemed to fix that) I'm stumped, any ideas? Could a bad pre-cat O2 cause this? I have one in the trunk and i know there was a problem with it when we did the top-end.

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could do it. O2 sensor isn't active until both a coolant temp and timer have been exceeded. could unplug it and see if that fixes it. you'll certainly get an SES for the O2 sensor, but it won't effect your fuel trims.

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Ok, I'll unhook that tommorow. got to get to the dang thing! Can i reach it by removing the upper mount and ratcheting it forward? I really don't want to take the UIM off again lol.Any other ideas if this does not work? Can't find a vacuum leak. There is a sensor on the intake arm (MAP?) that is not plugged in because it did not seem to have one in the 94 wire harness.

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94-95 LQ1 don't have a MAP sensor, so that's fine. maybe i'm used to the 91-95 intake, but the actual electrical connector for the O2 sensor should be able to be accessed without pulling the plenum. maybe the throttle body tube.

 

gray would imply oil, i would think... generally you'll get black from too much fuel.

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Coolant temperature sensor, perhaps? If it's reading exceptionally low, the ECM could be enriching the mixture.. Or, since it's been swapped, is it possible the coolant temperature sensor wasn't connected, and the ECM is reading that as low?

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no oil burn smell, just kinda a fuel smell, and oil lvl has not dropped. I just took it as a slightly rich mix. where is coolant temp sensor located? Is it possible to have a headgasket issue where the car drops compression when warm but uses no coolant or oil? I thik thats kinda a long shot but just wondering. we did the headgaskets when we swapped it as well (still has 94 heads and cam carriers)

Edited by 96montecarloz31
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ok coolant temp sensor is hooked up, but who knows if its reading correctly. I do get a temp reading on the gauge cluster, but idk if that is a separate sensor

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