89 S10 BLAZER ROUGH IDLE/STALLS

  • Tiny
  • Deeredude5510
  • 1989 CHEVROLET S-10

Engine: 4.3L
Auto Trans, 2WD, mIleage is about 215,000

This rig has a Goddwrench motor in it, not sure of replacement mileage, bought it used. It was at a very low idle and stalling a lot. GM tech scanned and had no codes. Timing is OK, EGR is new, IAC was replaced last night, it still doesnt run right. Now it seems as if a vaccum leak is the problem, but no ideas. When the heater or vent is on the idle deteriorates, but turning AC on bumps idle up to an acceptible level. My next guess. MAP sensor? Any help would be appreciated. Thank You in advance.

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Sunday, August 19th, 2007 AT 1:32 AM

3 Replies

  • Tiny
  • Rasmataz
  • MEMBER

Could be sticking throttle shaft or binding linkage that the TPS giving the PCM the curve ball of high voltage. Check the TPS voltage should read at close position 1.2volts.

Also check your battery connection fluctuation of voltages will change the position of the IACV.

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Sunday, August 19th, 2007 AT 4:44 AM
  • Tiny
  • Deeredude5510
  • MEMBER

Thank you for the info. I am about to lose my sanity over this thing. I will check on those tomorrow and see if that helps. If not off to the looney bin.

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Sunday, August 19th, 2007 AT 5:58 AM
  • Tiny
  • Deeredude5510
  • MEMBER

So today I took the throttle body off and the EGR passage was plugged. The gasket was toast and some less than brilliant light buld drilled out the idle plug and messed with it. Soooo.$50.00 and about 6hrs later I think I may have solved the problem. Also, new fuel filter. And then the kicker driving it around the block and asll the "do it yourself" spark plug wired that came with it fell apart. So. I think I fixed it. Time will tell.

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Sunday, August 19th, 2007 AT 10:48 PM

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