Missing when idling and under load

1994 CHEVROLET TRUCK
175,000 MILES • 5.7L • V8 • 4WD • AUTOMATIC
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MIKEHALE
  • MEMBER
  • 3 POSTS
my truck misses when idling and when your driving down the road, I did a compression test and all cylinders had around 165 psi, just installed new plugs and checked the dist cap roter and ignition module,wire and cap and roter was replaced last year
Sep 17, 2014 at 7:32 AM
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HMAC300
  • ✓Experienced Mechanic
  • 48,601 POSTS
heck for a vacuum leak at base of tbi unit at front and rear use choke cleaner and rpm changes it's leaking. then check all hoses for being soft and leaking as well.
Sep 17, 2014 at 8:20 AM
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MIKEHALE
  • MEMBER
  • 3 POSTS
I have already tried that, no change in idle
Sep 17, 2014 at 9:18 AM
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HMAC300
  • ✓Experienced Mechanic
  • 48,601 POSTS
then pull dist cap and check for carbon arcing as well as cracks and check plug wires 5000 ohms per foot including coil wire as that can go bac as well. finally scan for codes.
Sep 17, 2014 at 9:21 AM
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MIKEHALE
  • MEMBER
  • 3 POSTS
well I checked the cap and roter, they looked fine, the wires were replaced awhile back but I guess they could be bad, what about a weak coil or ignition module?
Sep 18, 2014 at 5:16 AM
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HMAC300
  • ✓Experienced Mechanic
  • 48,601 POSTS
y cold be that bu ti'm out of ideas so I have no further comments or suggestions.
Sep 18, 2014 at 5:33 AM
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