1990 CHEVROLET SILVERADO IDLES FINE BUT STALLS WHEN PUT IN GEAR.

  • Tiny
  • wa
  • 1990 Chevrolet Silverado
  • V8
  • 2WD
  • automatic
  • 100,000 miles

Truck stalls when I put it in gear. I have changed the TPS sensor, injectors, fuel regulator, plugs, wires, cap, rotor, coil, runs/idles strong but then put into gear and it stalls out. Any ideas would be great thanks. 1990 Chevrolet Silverado 350 V8 5.0L.

Monday, May 23rd, 2011 AT 4:32 AM

8 Answers

  • Tiny
  • Wrenchtech
  • Expert
  • 19,583 posts

You may have a bad IAC ( idle air control). Try eliminating any vacuum leaks and cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carburetor cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.

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Monday, May 23rd, 2011 AT 12:59 PM
  • Tiny
  • wa
  • Member

The IAC was it, I bought it took five minutes to install it and it fired right up and did not stall when I put it in gear. Thanks for the answers!

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Tuesday, May 24th, 2011 AT 6:02 AM
  • Tiny
  • Wrenchtech
  • Expert
  • 19,583 posts

You should still clean the throttle body to prevent further problems.

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Tuesday, May 24th, 2011 AT 10:32 AM
  • Tiny
  • silverado88red
  • Member

Hello. My 1988 does the same thing.I replaced the IAC and that did the trick I thought. An hour later I went out to check it and it was doing the same thing. Starts and runs great until I put it in gear, then it stalls unless I keep hitting the gas.

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Saturday, October 1st, 2011 AT 10:30 PM
  • Tiny
  • Wrenchtech
  • Expert
  • 19,583 posts

You need to start a new question of your own please.

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Sunday, October 2nd, 2011 AT 4:58 PM
  • Tiny
  • wa
  • Member

This was a friend of mines truck broken down at my house so I did not know this truck well. It had several things wrong with it and has over 200,000 miles on it. I was working with their low budget so I had limited funds available. It needed lots of repairs (fuel injectors, Throttle position sensor, Fuel Pressure Regulator, IAC, Distributor cap/Rotor/plugs/wires, starter, tune up items, etc) all because it was not well maintained. Along with the other things I replaced when I replaced the IAC valve I replaced the Fuel Pressure Regulator at the same time and inside the spring was broken, rusted and corroded. When I replaced them together it helped until operating temp kicked in but in the end I still had the stalling problem. What wound up really finally fixing it was the coolant temperature sensor. What I read at the library was when the truck first starts it runs on the main computer using those settings, but when it gets to operating temperature it goes off of it. It took me a while of checking everything I had repaired over and over and then I replaced the Coolant Temperature Sensor and it ran good after that. I do not think that part was too expensive either. Like $15-20 bucks. Hope all that helps you!

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Sunday, October 2nd, 2011 AT 7:24 PM
  • Tiny
  • silverado88red
  • Member

Thankyou!

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Sunday, October 2nd, 2011 AT 10:13 PM
  • Tiny
  • junerivera
  • Member

Hello. I am new to this page and I need some help. My friend has a 1991 Chevrolet Silverado pickup truck V8 c1500 5.7L. She is currently having the same stalling issues. It idles fine when parked but then stalls when put into drive or reverse. The idle drops quickly. Before this issue started happening, she had the truck sitting in her friend' s drive way for over a year. About two weeks ago I replaced her battery since it was dead and I changed the engine oil. Everything was fine with the truck until it started stalling a week later. Went out to check the truck today and cleaned the throttle body with carburetor cleaner, removed all the nasty carbon from all passages and replaced the IAC valve. It is still stalling in drive. The only way I was able to keep the truck from stalling was by putting a hard plastic piece on a small threaded stud on the throttle body that makes contact with the throttle lever when closed. This is keeping the idle at high and somewhat decent while it is in drive. Now it is only stalling when the steering wheel is turned all the way to the looking position, plus it tends to hesitate when accelerated. Any help or ideas will be helpful and appreciated. Thanks.

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Sunday, May 1st, 2016 AT 7:47 PM

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