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Discussion Starter · #1 ·
Seems like most 77 z owners I've talked to have this problem, and I'm looking for a solution. Under WOT to Mid throttle positions, when shifting, it backfires out the exhaust.Also, when revved in neutral, it backfires about when it hits 3500 rpm, on the way down. Otherwise it runs very strong (127 indicated) and gets 20 city, so I don't believe it's running too rich..Fuel level has no bearing on this little FI buggaboo. Any ideas or suggestions, please let me know. Thanks in advance!
 

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Discussion Starter · #2 ·
<b>RE: 77 problematic backfire, any solutions?</b>

Check for cracked AFM boot, replace Air Regulator . On mine the air regulator was an annoying intermitant problem .
 

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Could be an exaust leak. The leak under pressure blows out, but when the pressure is taken off (decell) it can suck raw air into the exaust pipe, giving the unburnt fuel there oxygen to burn, kabang, there's your backfire.

I could be wrong but I have seen this on V8's with header flange gasket leaks. Replace the faulty header gasket and the problem goes away. Check for exaust leaks.

Ken
 

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Discussion Starter · #4 ·
Well, I could totally be wrong here, but I had a very similar problem. I had a bad spot in my distributor. It took me forever to finally figure it out. I was thinking that it couldn't be that easy to just replace cap,rotor & wires. But it was. You might try it before you go to the more expensive alternatives.
Good Luck!
 
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