1997 GMC Sierra High idle and miss on #3 cyl

1997 GMC SIERRA
117,000 MILES • V8 • 4WD • AUTOMATIC
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BIGGUYMJ
  • MEMBER
  • 1 POST
I have a presistant miss and code (engine miss) on #3 cylinder,
I have changed wires, plugs, cap and rotor, I've cleaned the EGR valve and the Idle vlave on the intake. I have run several tanks of injector cleaner through the engine. I cleaned the MAF and MAP after cleaning them the idle went way up and now sits at 1100 RPM at idle out of gear and miss show up at idle in gear. Of course check engine light is on with engine miss code on #3
Suggestions?
Fuel pump was replaced at about 50,000 miles.
Oct 28, 2008 at 3:49 PM
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DENNYP
  • ✓ASE Certified Mechanic
  • 1,824 POSTS
  • ASE Certified Mechanic
Spray some brake clean around the intake manifold gaskets with the engine running to see if you have a vacuum leak.
Oct 29, 2008 at 4:42 PM
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