My engine stalls at idle?

Tiny
CHEVY269
  • MEMBER
  • 1990 CHEVROLET TRUCK
  • 5.7L
When the truck is up to operating temp it sometimes dies when you put it into gear when in park it does idle high then "not all the time but it happens more sometimes than others" when you put it under a load it just falls on it's face and bucks till eventually thing back to normal. I've read and read about it done everything my bank account could afford can't shoot In the dark anymore need some help
Friday, April 4th, 2014 AT 1:21 PM

28 Replies

Tiny
CHEVY269
  • MEMBER
  • 5 POSTS
I also checked for vacuum leaks and replaced the throttle body gasket I see the base gasket go out all the time on these trucks. Here is a guide to confirm.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please run down this guide and report back. Check the MAP sensor to make sure it holds vacuum
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Friday, April 4th, 2014 AT 1:34 PM
Tiny
CHEVY269
  • MEMBER
  • 5 POSTS
Can I check them without replacing or do I just have to buy new ones?
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Friday, April 4th, 2014 AT 2:59 PM
Tiny
CADIEMAN
  • MECHANIC
  • 3,544 POSTS
Check this guide and the EGR valve to make sure its not pulling on at idle.
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Friday, April 4th, 2014 AT 6:27 PM
Tiny
CHEVY269
  • MEMBER
  • 5 POSTS
Unhook the EGR or remove it?
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Friday, April 4th, 2014 AT 7:16 PM
Tiny
CHEVY269
  • MEMBER
  • 5 POSTS
Changed the tps and map no change gonna pull the cat next. It backfires on occasion when under a load dunno if that changes the possible problem also the coolant temp sensor is another thing I've changed so I replaced the throttle body gasket and that fixed the problem thanks for the suggestions this site rocks.
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Saturday, April 5th, 2014 AT 11:06 AM
Tiny
CADIEMAN
  • MECHANIC
  • 3,544 POSTS
Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.
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Sunday, April 6th, 2014 AT 7:27 PM
Tiny
BIGBENLEWIS
  • MEMBER
  • 1 POST
  • 1990 CHEVROLET TRUCK
  • V8
  • 4WD
  • AUTOMATIC
  • 130,000 MILES
1990 chevy 1/2 ton truck 350 engine. Engine loads up when attempting to rev and will not ilde. Checked egr sensors and distributor. Any ideas?
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Wednesday, November 25th, 2020 AT 8:20 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Clean and test the idle air control valve, TPS and MAP sensors-
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Wednesday, November 25th, 2020 AT 8:20 AM (Merged)
Tiny
CHEVY64DRIVER
  • MEMBER
  • 1 POST
  • 1990 CHEVROLET TRUCK
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
I have a 90 chevy k1500 the engine is shutting down after it warms up. It will run fine when cold but after warm up it seems like it is flooding out. Will start back up but have to hold fuel peddle to floor and it runs rough and can't drive it. It will stall when put in gear. But after it cools down for a few hours it will run fine for about 15 mins. Blows black when engine starts to shut down after warm up
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Wednesday, November 25th, 2020 AT 8:20 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check fuel pressure, if it's TBI which it shold be 9-11 psi. Check for a blown gasket under the tbi by spraying choke cleaner around it. If the rpm goes up or down it's leaking. Also check the hose going to the map sensor on the firewall, they get soft and suck together. Then the map doesn't work.
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Wednesday, November 25th, 2020 AT 8:21 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Could be running too rich check and test the following below-

1. Fuel pressure not within specs. Can be cause by restricted fuel return line or defective fuel pressure regulator.
2. Defective Oxygen Sensors.
3. Leaking injectors.
4. Coolant temperature sensor out of calibration.
5. Restricted air intake system.
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Wednesday, November 25th, 2020 AT 8:21 AM (Merged)
Tiny
OMALEY29
  • MEMBER
  • 2 POSTS
  • 1990 CHEVROLET TRUCK
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
So I have a 90 Chevy Silverado K1500 4x4. 350 tbi system auto trans. It started to stall when I was driving I pulled over and just gave it some gas for a min. It started to run fine then drove about 8 miles home. Drove it a few more times then I get in it and it turns off when I put it in gear. Runs fine when I give it gas. I am guessing fuel pump going to rent tool to check the pressure. But would low fuel pressure cause the truck to ideal up and down also or should I be looking at intake manifold leak. Bought truck used for 1,000 bucks from dealer so dont know any history on it.I have change the TPS. Ideal air control. EGR, cap rotor plugs wires.
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Wednesday, November 25th, 2020 AT 8:21 AM (Merged)
Tiny
WA
  • MEMBER
  • 6 POSTS
Same issue here what did your problem end up being? 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 Chevy Silverado 350 V8 5.0L
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Wednesday, November 25th, 2020 AT 8:21 AM (Merged)
Tiny
VEGASMSTRJ
  • MEMBER
  • 50 POSTS
  • 1986 CHEVROLET TRUCK
Hi everyone.I have an 86 Chevy Silverado with a mostly stock 305 and 700r4 tranny. The motor has like 270,000 miles on it! About 2 months ago I had the timing chain, gasket, valve cover gaskets, and intake gasket replaced. I put a holley carb on it and it was tuned also. Recently I flew home and my truck sat for 10 days. When I returned, it started instantly and had no problems, but as I was driving home (90 miles) I filled up with regular fuel even though I usually run premium(damn gas prices). The truck was a little sluggish but I thought it was normal because of the fuel. I stopped at a stop street and it stalled. When I try to accelerate, its really sluggish and makes popping sounds. I checked under the hood and played with it a little bit and saw black smoke from the valve covers when I rev it. It also looks like some oil sitting on the intake towards the back, maybe from bad intake gaskets? I did make it back safely. The next day I filled it up with premium and got some fuel system cleaners and sprayed the carb with carb cleaner. Still no help! I probably should add that I pulled the dual exhaust pipes apart so I could have really loud wide open headers because I live on a military base and they dont care. But I'm not sure if doing that for a while will mess with the engine or not. I'm hoping its not a serious engine problem, but I guess that's to be expected with an old vehicle. Any thoughts or suggestions would be awesome! Thanks!
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Wednesday, November 25th, 2020 AT 8:21 AM (Merged)
Tiny
VEGASMSTRJ
  • MEMBER
  • 50 POSTS
Nope, it originally had a Rochester 4bbl carb.
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Wednesday, November 25th, 2020 AT 8:21 AM (Merged)
Tiny
VEGASMSTRJ
  • MEMBER
  • 50 POSTS
I was told to change the fuel filter, so I did. No change. :( Also I checked the oil and it looked black like usual and smelled normal.
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Wednesday, November 25th, 2020 AT 8:21 AM (Merged)
Tiny
PALCO
  • MEMBER
  • 83 POSTS
The black smoke from the valve cover area on accel. Running with open headers. Poping, slugish. I'd say you have a worped and/or burnt exhaust valve or two. When you run open header and the turn the engine off. The thin walls of the header(as aposed to thicker casting of a normal manifold) cools realy quickly and as it cool draws up cold air to the still hot valves. Still nesseled in a warm water thick casting. And any open valve can worp. And a cyl. In the sweet spot can let cool air into the comustion chamber and get an intake valve also. Thats why when you run a full exhaust sys. You get condensation in the muffler. Witch comes out as steam while warmig up the car. Good luck
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Wednesday, November 25th, 2020 AT 8:21 AM (Merged)
Tiny
VEGASMSTRJ
  • MEMBER
  • 50 POSTS
Hmm. That sucks. The truck is still running and the problems have'nt gotten better or worse. How long can I drive it before it blows up and anyone have an idea how much it would cost to repair?

Thanks!
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Wednesday, November 25th, 2020 AT 8:21 AM (Merged)
Tiny
ROLFESJ
  • MEMBER
  • 3 POSTS
Do you or a friend have the capabilities of running a compression check?

I would also check the spark plug wires to make sure some one has not crossed them for you.
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Wednesday, November 25th, 2020 AT 8:21 AM (Merged)
Tiny
VEGASMSTRJ
  • MEMBER
  • 50 POSTS
I will definately look into a compression test, but im sure I have the plug wires right. Thanks for the post!
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Wednesday, November 25th, 2020 AT 8:21 AM (Merged)

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