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Discussion Starter · #1 ·
Hello my name is Heath and my 94 trans am is being a pain in the a**. I've been working on it since I bought it almost 1 year ago. I need help with a spark issue I have. It will crank start and run great for a while but then dies like you turned off the switch. I can idle for hours and then die and won't start back for a while. Once it starts back it runs good. It seems to only die while driving when it hits higher rpms (4000 to 5000). It has brand new fuel pump injectors fuel rail fuel pressure regulator fuel filter. Fuel isn't an issue I've already fixed that problem. Any help would be greatly appreciated. Thanks in advanced.
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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Have you scanned it for codes? Heat soak can affect the optical cam position sensor in the Opti, or the ignition control module (ICM). Both failures set codes, and neither turns on the SES light.

I assume you have verified the fuel pressure under max engine load - on the road, WOT, over 5,000 RPM.
 

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Discussion Starter · #3 ·
No I haven't checked for codes. I've tried but the old paperclip trick doesn't work on my 94 and an obd1 scanner has been hard to find. I need to add that I have good spark until it dies then I have no spark and when it finally does start back it idles high.
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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14,425 Posts
1993 is the last year the paper clip would work.

Go to the PCM forum and look for the "pinned" post for Scan9495.... free download of the best LT1 scanning software. All you need is a laptop and a cable you can buy or build.

Both the IAC and the Opti sensor could result in loss of spark.

For a quickie check, go to:

www.shbox.com

Open the tech page, click on "How To's", look for article #28 - "Prove Optispark Signals Are Getting To The Coil".

This thread should really be in the "Fourth Generation..... " forum for best results. I can move it there if you want.
 
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