1991 GMC Sonoma rich fuel

1991 GMC SONOMA
130,000 MILES • 2.5L • 4 CYL • 2WD • MANUAL
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SKIPR
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  • 3 POSTS
Rebuilt TBI. Replaced Idle air control sensor (duralast AC106) and the throttle control sensor/module (Duralast EC1033P). Starts high idle within 5 Minutes idles down. I noticed it is running rich and has a slight but irritating miss. Advise
Jul 18, 2014 at 1:15 PM
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HMAC300
  • ✓ASE Certified Mechanic
  • 48,601 POSTS
  • ASE Certified Mechanic
make sure there is no vacuum leak at front and rear of tbi unit. if hose going to map sensor is soft replace it. normally when iac is replaced you have to drive 40 mph to set it. then scan for codes.
Jul 18, 2014 at 3:31 PM
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SKIPR
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Appreciate the quick response. Performed the functions and discovered a sticky throttle cable. The cable sticks when cold. After it engine is operating temperature it is fine. Not sure the next step. By the way is there a special
Timing light to check the timing?
Jul 31, 2014 at 8:23 AM
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HMAC300
  • ✓ASE Certified Mechanic
  • 48,601 POSTS
  • ASE Certified Mechanic
o special timing light if I remember right you have to disconnect brown/black wire on pass side to time it. try lubing the cable
Jul 31, 2014 at 9:27 AM
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SKIPR
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I will take a gander and use what you've provided. Again thanks
Jul 31, 2014 at 9:39 AM
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HMAC300
  • ✓ASE Certified Mechanic
  • 48,601 POSTS
  • ASE Certified Mechanic
also check for a vacuum leak at base of tbi unit front or back as well as soft hoses and cracks on them
Jul 31, 2014 at 10:06 AM
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