On scanner it pulls up water temperature control sensor

1998 CHEVROLET SILVERADO
115,000 MILES • 7.4L • V8 • 2WD • AUTOMATIC
Avatar
JAMESDUPE
  • MEMBER
  • 1 POST
Changed sensor twice. Runs at about 120 degrees. Backfires when stomped and it seems like it misses at every time transmission shifts. also, changed fuel filter, spark plugs, wires, rotor and distributor cap.
Apr 3, 2018 at 5:15 AM
Advertisement
Avatar
STEVE W.
  • CERTIFIED EXPERT
  • 15,116 POSTS
Have you verified that the thermostat is actually operating? Also, check over all the vacuum lines for leaks. It sounds like you may have a sticky EGR valve as well.
Apr 3, 2018 at 12:51 PM
Avatar
JAMESDUPE
  • MEMBER
  • 1 POST
I have not checked it (thermostat) if there is one. i do not know where all vacuum lines are.
Apr 3, 2018 at 10:22 PM
Advertisement
Avatar
STEVE W.
  • CERTIFIED EXPERT
  • 15,116 POSTS
The thermostat range on that engine is 188 - 205 degrees F. 120 is way low. A stuck open thermostat would cause it to run cold.

Should be a sticker showing the vacuum lines. This is the base diagram for that engine.
Image (Click to enlarge)
Attached Media
Apr 3, 2018 at 11:51 PM