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Discussion Starter · #1 ·
bought and installed new gm high performance opti, installed and still having missfires and now backfiring on acceleration. checked all connections atleast 4 5 times and checked plug wires and plug wire order atleast 4 times,, before install i looked at the picture i took and the old distributor and made sure it was in properly,,,and ideas???
 

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It sounds like a rare occurrence but give this a thought, there have been a few times a car acted up like this and the solution came from an unlikely idea, the wires on the rear o2 sensors could have been mixed up and crossed if anyone had anything to do back there. Try swapping the connections and see what happens.
 

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Is the car throwing any codes?

If so, get them and report back.
 

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Discussion Starter · #5 ·
no codes from the tech 2
 

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Discussion Starter · #6 ·
got rid of the backfire still a miss tho
 

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Discussion Starter · #8 ·
cylinder 5 is the one missing and is at 44 psi cranking compression and at TDC on #5 i am getting 95% leakage out of the exhaust...:cool:
 

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44PSI! :eek:

I'm not sure what your problem is, but I know that's a big problem.
 

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Misfire

You didn't mention spark plugs- I had miss (bucking) no engine code popped up. New set of Champions solved problem. ( Recommended vs AC by shop that installed my Paxton). Also rare but 'new plug' could be defective.
 

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You didn't mention spark plugs- I had miss (bucking) no engine code popped up. New set of Champions solved problem. ( Recommended vs AC by shop that installed my Paxton). Also rare but 'new plug' could be defective.


Spark plugs are not the problem if his cylinder has 44PSI.

Plugs are pulled for compression tests.
 
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