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Discussion Starter · #1 ·
Hello, I have a 95 caprice with the LT1. My problem is lately when my car warms up and I am driving on the hi way it runs fine, once I want to pass someone or merge onto a hiway my car has a total loss of power and I can hear it backfiring from the front thinking out my intake. Once I let off the gas it will drive fine, only happens when I am going to pass and when my car goes to downshift it just sputters and pops. had to pull over on yhe side lastnight because I was going up a hill and my car just did not want to do just backfire, got on the shoulder and sat there with it running for a min then I was able to get home
 

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Discussion Starter · #3 ·
Thanks for your help, today I put a gas gauge on my car and took it for a rip!! I also checked my vent hose for the opti and it is okay it was new lastyear and the opti. So when I got on the hi way my car runs great untill I get it hot, so I went to pass someone and it all started again my car would bog and sputter and I had to pull back in the slow lane and drive like a pussy, as it was happening my gauge was reading 38 - 40 psi so I know it is not a gas issue
 

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Coil wire, ICM, O2's. all have issues when old and get's hot.
 

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Discussion Starter · #6 · (Edited)
if I was to unplug my o2 sensors would that not make my car run like more ****, how would it run well with them unpluged? Would it not run very rich, screwed up air mixture, throwing codes etc. I just don't see how to unplug them it will run better, please explain
 

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if I was to unplug my o2 sensors would that not make my car run like more ****, how would it run well with them unpluged? Would it not run very rich, screwed up air mixture, throwing codes etc. I just don't see how to unplug them it will run better, please explain
with the O2's unpluged it keeps the PCM in open loop, if it runs better the O2's are bad or you have a exhaust leak before the O2's
 

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As stated above, it also "locks out" the o2 milivolts to .443 volts. This keeps the car in normal timing mode versus knock retard or low octane mode. It puts the car in a "version" of open loop. It exists in the pcm as a field test for drivability technicians. Such as unplugging and removing the o2's for catalyst restriction tests. If the car runs worse with them unhooked you have a mechanical fault and not a "learned" fault due to an engine management fault. The point is to remove the pcm's ability to adjust the fuel trims based on data that could be flawed. Is that more clear? LMK.

Chris
 

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Discussion Starter · #10 ·
Very clear thank you very much!!! OK so I unplugged them and took it for a ride once again the car ran great when I first got on the hi way passing cars downshifting great and everything. After 5 min I went to do another pass and bamm not power, poppingn backfiring. Once I let off I can drive fine and slowly get up to 120 but if I put my foot down hard at all it all starts
 
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