1998 Chevy Silverado stalling issues

Tiny
CHADLAUGHTER
  • MEMBER
  • 1998 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 174,000 MILES
My 98' Silverado just started stalling 2 days ago; when I put it into park or slow down. It doesn't sputter it just shuts off. Now I have to turn it over a couple of times before it will start. I checked all of the plugs and wires (they were recently replaced) and they're not bad. The battery is keeping a good charge and I haven't had any drop in oil pressure. The check engine light is not on. I'm confused.
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Saturday, September 25th, 2010 AT 4:38 AM

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Tiny
MERLIN2021
  • EXPERT
On the throttlebody check the IAC(idle air control valve) you can try removing it and cleaning any carbon out of it, but if it's weak, a new one would eliminate the stall on de-cell or idle.
IDLE CONTROL SYSTEM Idle Air Control (IAC) System Diagnosis) 1. If powertrain OBD system check has been performed, go to next step. If powertrain OBD system check has not been performed, perform powertrain OBD system check. See POWERTRAIN OBD SYSTEM CHECK in TESTS W/CODES - 5.7L article. 2. Turn ignition switch to LOCK position. Connect IAC Driver (J-37027-A) to IAC valve. Set parking brake and block wheels. Turn A/C off. Start engine and let idle. Using scan tool, display RPM. Extend and retract IAC valve using IAC driver. If engine RPM changes, go to next step. If engine RPM does not change, go to step 7). 3. If RPM changes smoothly with each flash of IAC driver between 700 and 1500 RPM, go to next step. If RPM does not change smoothly with each flash of IAC driver between 700 and 1500 RPM, go to step 7). 4. Disconnect IAC driver. Check resistance between appropriate IAC valve terminals. See IAC VALVE RESISTANCE table. See Fig. 3 . If resistance is as specified, go to next step. If resistance is not as specified, replace IAC valve and go to step 10).


http://www.2carpros.com/forum/automotive_pictures/62217_iac_resist_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_IACA_1.jpg


5. Check harness between PCM and IAC valve harness connector for opens and shorts. If open or shorts do not exist, go to next step. If open or shorts exist, repair as necessary and go to step 10). 6. Check the following: mechanical malfunction, vacuum leaks, lean or rich mixture, poor connection at PCM, defective PCV valve, A/C compressor circuit for short to ground, poor connection at IAC valve or IAC valve passages for blockage or restrictions. If problem does not exist, go to step 9). If problem exists, repair as necessary and go to step 10). 7. Check IAC passages for blockage or restrictions. If blockage or restrictions do not exist, go to next step. If blockage or restrictions exist, repair as necessary and go to step 10). 8. Replace IAC valve and go to step 14). 9. Replace PCM and go to next step. 10. Connect IAC Driver (J-37027-A) to IAC valve. Start engine. Using IAC driver, extend and retract IAC valve. If RPM does not change as expected, go to step 3). If RPM changes as expected, system is okay at this time.
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Saturday, September 25th, 2010 AT 11:09 AM

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