'99 Sierra C2500 Stalls After Hard Stop

[stonefly65]

Hi all. New to this board and hope someone can help. I've been experiencing engine stumble at idle and when aproaching a hill climb but the weirdest thing is how it stalls after a hard stop after braking. It will start right up afterward. I've cleaned injectors replaced fuel filter, cleaned MAF, checked for worn plug wires. She's in her twilight with nearly a 1/4 mil miles but I need her last through this bad economy.

Thanks in advance for any input.

[stonefly65]

Hi all. New to this board and hope someone can help. I've been experiencing engine stumble at idle and when aproaching a hill climb but the weirdest thing is how it stalls after a hard stop after braking. It will start right up afterward. I've cleaned injectors replaced fuel filter, cleaned MAF, checked for worn plug wires. She's in her twilight with nearly a 1/4 mil miles but I need her last through this bad economy.

Thanks in advance for any input.

 

 

5.7 liter by the way

[pennzoil29]

With that many miles, you might be looking at a timing chain issue, or distributor gear might be worn. Have you changed the dist cap and rotor lately, fuel pump might be on it's way out. These are just idea's for you to consider. By the way, welcome aboard.

[green 788]

I'd throw a Throttle Position Sensor at it and see what happens. If that doesn't fix it, you'll at least have a new one installed. Under 40 bucks most places...

 

By the way, I've got a 5.7 in my 1996 GMC. Has your engine been overhauled in those 250K miles? Just wondering...

 

Dan

[stonefly65]

With that many miles, you might be looking at a timing chain issue, or distributor gear might be worn. Have you changed the dist cap and rotor lately, fuel pump might be on it's way out. These are just idea's for you to consider. By the way, welcome aboard.

 

 

Cap and rotor are next to be replaced. I changed the fuel pump at about 100k...when it went, it went all at once, no warning. I'm hoping its not the pump.

Thanks for the suggestion.

[stonefly65]

I'd throw a Throttle Position Sensor at it and see what happens. If that doesn't fix it, you'll at least have a new one installed. Under 40 bucks most places...

 

By the way, I've got a 5.7 in my 1996 GMC. Has your engine been overhauled in those 250K miles? Just wondering...

 

Dan

 

No overhaul yet. I need to get about another 5000 miles out of it before I get a new rig. I use this truck for my business. Dan, where is the TPS located?

[green 788]

It's on the throttle body, you can see it pretty easily on the driver's side of the throttle body...

 

You can go by Advance Auto or Auto Zone and have them scan your truck for codes. They'll do it for free. Often, codes will show up in the scanner which will not light the service engine light.

 

You might have a TPS (throttle position sensor) code showing. It's easy to change, you just use a torx bit and remove two screws and then put the new one in.

 

Let us know what you find. And I'm glad to know that my 5.7 has the potential to make it over 200K without an overhaul.

 

Dan

[green 788]

check this link from another member...

 

http://www.gm-trucks.com/forums/index.php?showtopic=84608

 

...second photo down, you'll see the TPS in the bottom portion of the photo. If you pick up another from the auto parts store, you'll be able to compare the appearance so you'll know for sure where the part is located on your engine.

 

Good luck.

 

Dan

[stonefly65]

check this link from another member...

 

http://www.gm-trucks.com/forums/index.php?showtopic=84608

 

...second photo down, you'll see the TPS in the bottom portion of the photo. If you pick up another from the auto parts store, you'll be able to compare the appearance so you'll know for sure where the part is located on your engine.

 

Good luck.

 

Dan

 

Thank you very much for the help. As soon as I get the opportunity I'll get down to Auto Zone.

 

Mark