1992 Gmc Sierra 1500 Guage Problem / Missing

[sbdblyss]

Hello,

 

Sorry about mis-spelling in title.

 

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 gauge 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

[email protected]

[GMstrong]

could be alot of things.plug gap incorrect,crossed spark plug wire,fuel pressure might be low,bad ignition module,egr valve will cause a miss too,map sensor,egr vacuum solenoid,what kind of intake gaskets did you use?whats your timing at?

[GMstrong]

check for vacuum leaks also..read this..stick a paper clip in the A,B jumper right under the steering colunm see what codes you get.http://www.troublecodes.net/GM/89_577_tbi.shtml

[sbdblyss]

could be alot of things.plug gap incorrect,crossed spark plug wire,fuel pressure might be low,bad ignition module,egr valve will cause a miss too,map sensor,egr vacuum solenoid,what kind of intake gaskets did you use?whats your timing at?

 

Plug gap is correct. I had Bosch plugs, but order stock plugs from GM and made sure the gaps were correct. Spark plug wires are not crossed, I just double checked it and made sure it was correct using my Haynes manual. I used felpro gaskets for the intake. Timing is at 0. Already replaced the map sensor.

 

 

I have not checked the fuel pressure, but I will do so tomorrow evening. I was wondering if it could be the ignition module! Is there any way to test it, as well as the EGR sensor and solenoid?

 

check for vacuum leaks also..read this..stick a paper clip in the A,B jumper right under the steering colunm see what codes you get.http://www.troublecodes.net/GM/89_577_tbi.shtml

 

I did check for vaacum leaks and there are none that I know of. I used starting fluid and sprayed it everywhere. My ECM is not storing any codes.

[GMstrong]

Well first off does your edelbrock even have a egr provisions?i would just replace it i would have done that when you did the cap.and another thing i didnt hear you say the rotor?for the dis cap.if its none of these then you have a computer problem.

[sbdblyss]

Well first off does your edelbrock even have a egr provisions?i would just replace it i would have done that when you did the cap.and another thing i didnt hear you say the rotor?for the dis cap.if its none of these then you have a computer problem.

 

I'm sorry, I don't know what you mean by the intake being provisions for the egr valve. I replaced the cap and rotor twice. I appreciate your help! I just need a bit more insight on the egr provision. I will pick up another computer tomorrow and see what happens as well. Thank you!

[Mike G]

I was having problems similar to this at one point. I brought it to a speedometer shop to fix and they found a bad ground up front behind the battery.... That said, double check all your electrical ground connections between the frame/battery and motor.

--Mike

[Debo511]

G100 battery cable to frame, make sure mounted to the frame and not the core support.

[GMstrong]

Some aftermarket intakes dont even have egr ports i was asking if yours did.if it doesnt then it might throw code and have a hard time passing inspection.yea check your grounds make sure its a clean ground not rusted or corroded.