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1992 Chevy Scottsdale K1500 4.3L V6
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Discussion Starter · #1 ·
There is something strange with my truck...

I have changed out the TBI and replaced the gaskets on it. Replaced the TPS and the IAC... Drives better.
When the weather was VERY HOT about a week ago, it would almost die when the RPMs would drop. That was before I changed the those two components.

At the moment, it seems the temp has stabilized and it does the dying act much less. I went to a mechanic friend who took a look at it - the fuel and the vacuum leaks...

Changed:
IAC
TPS
MAP
Vehicle does not have IAT or purge valve/solenoid.

Not sure about fuel pump at the moment. I am not prepared for that undertaking of messing with the bed of the truck... need some friends for that one...
 

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98 gmc k1500 5.7
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510 Posts
before you change the fuel pump , put a pressure gauge on it, you might have to do it under the truck at the fuel filter as i dont know enough about that year to tell you if it has a pressure port, but thats where i would start
 

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‘01 Silverado 2500HD 8.1/Allison 5sp xcab long bed
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3,622 Posts
I agree with checking the pressure. The ‘92 didn‘t come with a port. Has to be a TBI test kit with an adapter installed on the supply line

Or you can put one on permanently.
169864


14psi regulator spring doing its job.

I did some other mods as well, but having the pressure gauge permanent gave me a heads up that my pump was failing miserably. It went down to 4psi. The photo above was taken after I replaced the garbage one with one for a ‘97 Vortec engine. Never had another fuel issue.
 

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1992 Chevy Scottsdale K1500 4.3L V6
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19 Posts
Discussion Starter · #4 ·
Let me see if I can explain what it is doing...

I will drive along for a couple of minutes at speed... 35 - 45... When I clutch it at a light/sign... The RPMs drop almost like it wants to die... then it comes back up to between 1,500 and 1,800... otherwise it drives good... sometimes the start is a bit rough... No backfires, it does seem to lack some power in the top of the gears before needing to shift. Does that sound like a fuel pump?
@Crispyt
 

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‘01 Silverado 2500HD 8.1/Allison 5sp xcab long bed
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3,622 Posts
Yes. Check your pressure.
 
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Start with fuel pressure first and go from there like others have said. My 95 did this about 10 years ago, I would slow down to take a turn or pull into the driveway and it would either die out or stumble a bit then come out of it. In my case it was the fuel pump failing. Since it's intermittent I would say it's a fuel pump but it doesn't hurt to check ground wires too. I have also had a bad ignition switch on mine cause weird issues like that, but the only difference was it would cause my dash cluster to reset itself when it messed up. Usually ignition coils, and ignition control modules will be more consistent when they fail.


Just on a side note... Have you messed with the distributor timing or checked to make sure that it's correct? In reality if it's off it would probably be a more consistent issue but it might not hurt to check it out. Also make sure that the shaft is tight and doesn't have any side to side play, sometimes the bushings go bad and they start to eat into the pickup coil.
 
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