Hello, I have a 1995 GMC Sierra K1500 5.7 liter.
The problem I am having with my truck is only observed when it is warm, when the temp reaches ~170F, it will start cutting out when it reaches 1800 rpm, then as it gets warmer it’ll start doing the same thing at 1500 rpm, and the cycle keeps going until the truck eventually chokes itself out and completely shuts off. When cold it will idle and run COMPLETELY fine, it will not cut out at all and will run like an absolute champ. When warm and idling it’ll also do the same thing as mentioned above, it’ll choke itself out. I have had the truck at 75 mph when cold and there’s not a single problem, though I can’t say the same when it eventually warms up. I did the paper clip method, as I could not find anybody who had an OBD-1 code scanner, and it showed a code 32. I cleaned the EGR valve because it was stuck, and made sure the plunger worked. I also put a lower degree thermostat. Also I should mention, I have cleaned the idle air control valve and have tested the TPS, which when testing, checked out good. I rechecked the fuel pressure and it’s within tolerance. Prior to this work I’ve done to the truck, I purchased it non-running with a bad transmission pump, replaced the pump, transmission works perfect.
This is what I’ve done so far:
-New 195 degree thermostat
-New fuel pump
-New fuel filter
-New Distributer Cap
-New Rotor Button
-New Spark plugs and wires
-New ignition control module (Noted: When I replaced the ignition control module, it ran flawlessly at any temperature for about 100 miles, then the truck sat for about 4 days, when crunk up and drove again, as it got warmer it started cutting out again as it did before)
- Replaced both temperature ascending units
Any help would be GREATLY appreciated!!