Engine is stalling out?

Tiny
AAWILS01
  • MEMBER
  • 1991 CHEVROLET SILVERADO
  • V8
  • 2WD
  • AUTOMATIC
  • 11,000 MILES
I own a 1991 Chevy Silverado 1500 with a 5.7L engine. When you drive it up even a slight incline it acts like it does not want to run. It cuts out and backfires. When sitting at idle it will increase rpm the drop rpm and want to die. I figure it is a sensor problem. I need a place to start though
Tuesday, November 2nd, 2010 AT 8:05 AM

21 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
The first thing to look at would be all the secondary ignition components such as dist cap, rotor, wires and plugs. Check out this guide

https://www.2carpros.com/articles/engine-stalls

Please run down this guide and report back.
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Tuesday, November 2nd, 2010 AT 8:28 AM
Tiny
AAWILS01
  • MEMBER
  • 3 POSTS
Changed the cap, rotor, wires, and plugs in Jan. Or Feb. Last year. Checked the plugs and the number 1 cylinder plug had so much corrosion on it the gap was almost closed. But it was the only one with a problem. I replaced it and still had the same problem.
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Tuesday, November 2nd, 2010 AT 12:16 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
That doesn't mean they can't have a problem now. You could have cracked a cap at any time or have a damaged plug or wire. It needs to be diagnosed properly to determine what is going on.
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Tuesday, November 2nd, 2010 AT 12:19 PM
Tiny
AAWILS01
  • MEMBER
  • 3 POSTS
I pulled the cap and rotor off last night and did not see any cracks or problems, I inspected all the wires and there were no breaks or melted spots. When I reassembled I checked for spark at all the cylinders and had a good spark at each.
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Wednesday, November 3rd, 2010 AT 9:33 AM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
You haven't checked anything thoroughly enough to rule anything out. Your going to need some help and test equipment.
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Wednesday, November 3rd, 2010 AT 9:39 AM
Tiny
REDC338
  • MEMBER
  • 7 POSTS
  • 1991 CHEVROLET SILVERADO
  • 149,000 MILES
My truck developed a miss. I did a complete tuneup, new coil, new EGR, rebuilt TB with injectors. This truck will run like a watch for the first 10-15 miles. Then it will start a slight stumble when I accelerate and it will gradually get worse until it shut's off completely. It will restart everytime but with the same issue. If I wait 5 minutes it will go for a few miles but then shut off again. I found no codes jumping out the diagnostic port. I even gave it a code by removing the TPS wire just to see if it would give a code and it did. I also have found unplugging the air sensor on the TB does nothing. No code, no engine trouble
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
CADIEMAN
  • MECHANIC
  • 3,544 POSTS
Start by checking the fuel pressure.
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
REDC338
  • MEMBER
  • 7 POSTS
I'll have to buy a gauge and a filter jumper. And It will do this in park Idling, after the 20 minutes of driving, so I can check it safely, not hanging out my door on the highway!
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
REDC338
  • MEMBER
  • 7 POSTS
Is it normal for a pump to lose pressure gradually like that? Then start right back up?
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
REDC338
  • MEMBER
  • 7 POSTS
I also noticed the relay seems hot
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
CADIEMAN
  • MECHANIC
  • 3,544 POSTS
Rent the gauge from the parts store. Get the gauge hook it up lay the gauge on the wiper arm so you can see the gauge dial. Then close the hood leave the hood on the safety latch. Drive the truck and when it quits read the gauge. Then come back. Gm pumps overheat and stop and than will run ok again till they stop again. Also the hose from the pump to the sending unit gets porce and it sucks air.
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-2
Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
REDC338
  • MEMBER
  • 7 POSTS
On a 91' there is no test port/Shrader valve. I'll have to remove the filter and "T" off with a hose
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
CADIEMAN
  • MECHANIC
  • 3,544 POSTS
When it quits spray the intake with starting fluid. Does it restart?
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
REDC338
  • MEMBER
  • 7 POSTS
I actually thought of doing that as it is cutting off. It will restart on it's own everytime, first crank
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
REDC338
  • MEMBER
  • 7 POSTS
I'm replacing the pump and relay this weekend. If this doesnt fix it, my next purchase will be dynamite!
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+1
Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
CADIEMAN
  • MECHANIC
  • 3,544 POSTS
Gm pumps get hot and stop and go like that. Good luck let us know what happens.
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
ARTHUR HOBBS
  • MEMBER
  • 1 POST
  • 1991 CHEVROLET SILVERADO
  • 198,000 MILES
5.7 Eng idles good, run good while driving however under light thottle at start engine runs ruff and will stall. Plugs, cap, rotor wires replaced
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
RIVERMIKERAT
  • MECHANIC
  • 6,110 POSTS
Here are a few additional areas to consider:

Idle Air Control (IAC) Valve:

Vacuum Leaks:

Throttle Position Sensor (TPS):

Fuel Delivery:

Mass Air Flow (MAF) Sensor:

Idle Control System:
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
CHEVYFORLIFE
  • MECHANIC
  • 33 POSTS
Try and in plug the vacuum line off of the egr valve and plug it with something. If the valve has a hole in the diaphragm you will get a tip in misfire.
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Thursday, September 3rd, 2020 AT 12:59 PM (Merged)
Tiny
RICKY GEORGE
  • MEMBER
  • 1 POST
  • 1991 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 125,000 MILES
I have a 91 chevy silverado it runs good for about 30 mins and then it just dies what is the problem?
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-1
Thursday, September 3rd, 2020 AT 12:59 PM (Merged)

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