1992 Gmc Sierra 1500 Guage Problem / Missing

[sbdblyss]

Hello,

 

1992 GMC Sierra 1500 5.7L V8

 

My truck is acting very odd, and it has been for some time. It runs fine, but after a few minutes, the Speedometer and RPM guage start to jump (rise, then lower, then rise, sometimes until they are at stuck at maximum) and the truck acts like it's missing every time this happens. Sometimes the truck just shuts off. This video is not of the truck having extreme symptoms. I am raising the RPM on my own, then the speedometer jumps up, and the check engine light flashes on and the truck misses. When I don't give it any throttle, the truck idles below normal, but sometimes (toward the end of the video), it runs normal and has no problems. I am hoping someone has an idea of what could be causing the trouble.

 

Video of problem: http://www.youtube.com/watch?v=H4N65Zzqspw

 

I have replaced the distributor (twice), the Distributor Cap, the Spark Plugs, the Spark Plug Cables, the battery (twice), the ECM (Not sure if it's referred to as the ECM, ECU, Computer), the Throttle Position Sensor, the Coil, the Speed Sensor, the Throttle Body, and the Alternator. There may be more, but I don't remember. This has all been replaced in an attempt to fix this same problem. The distributors seemed to make it better for about 30 minutes at a time, which seems wierd to me, but nothing really helped the problem.

 

I installed an Edelbrock Performer intake manifold before this happened, but this problem didn't come about until about 3 months after installation. If needed, I have a lot of pictures of the wiring, etc....

 

 

 

 

Thanks for any advice you may have!

 

Jake

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