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Old 04-07-2011   #1
rjhurst
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GTA Year: 1990
GTA Engine: 350 TPI Automatic
Bad misfire HELP!!!

Okay i have a 90 350 TPI with a sparatic misfire, that throws a code 42 randomly... I have been doing research and looking into it and just can not figure it out... what i have done so far is put new plugs wires cap rotor coil ignition module and IAC in and still the same.. misfires at idle and up to about 3500rpm has all kinds of power still... i just have no idea any help would be greatly appreciated
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Old 04-08-2011   #2
YumikoGTA
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Re: Bad misfire HELP!!!

Are you sure that all of your spark plug wires are reconnected tight? I had somewhat of this same problem a long long time ago when I began to work on my GTA myself in the 1990s. I forgot to fully connect the wire that connects onto the coil that goes to the very center of the distributor cap.

And there was another time when the wires that connect to the electronic ignition module was loose. That also made my GTA misfire really badly. So check those things.

Yumiko
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Old 04-09-2011   #3
rjhurst
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GTA Year: 1990
GTA Engine: 350 TPI Automatic
Re: Bad misfire HELP!!!

Thanks for the advise and i recheck all the wires and and recheck timming and every thing is a go!! but still has a misfire i thought maybe the timing was off since i timed it with the IAC stuck at 140 but timing was dead on... thanks any advise would be great!!!!
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Old 04-11-2011   #4
GTAhot92
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Re: Bad misfire HELP!!!

What again is a code 42? Sorry no where near a manual.
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Old 04-13-2011   #5
YumikoGTA
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Re: Bad misfire HELP!!!

Quote:
Originally Posted by GTAhot92 View Post
What again is a code 42? Sorry no where near a manual.
This is what I found on line about it:

Code #42:

1) fault at the electronic spark timing circuit,
or
2) fault at the direct ignition system,
or
3) fault at the fuel cutoff relay circuit.


I hope that this will help you.

Yumiko
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Last edited by YumikoGTA; 04-13-2011 at 05:17 PM.
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Old 04-13-2011   #6
rhomanski
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GTA Year: 1988
GTA Engine: 350 TPI Automatic
Re: Bad misfire HELP!!!

Code 42 will be set when you disconnect your wire for setting basic timing. Try clearing it and see if it comes back.

Regards,

Ron.
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