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Discussion Starter · #1 ·
A mechanic had it for a month and couldn’t fine vac leaks. I drove it to day and it consistently died at every light. I stopped and topped off the tank(6gals) and when I got home gas was dripping out of the gas filler at the cap when the truck was in the sun 90 degrees here today. Could this two problems be related?
 

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2000 Silverado Z71 4x4 5.3L 480k+ miles w/ GM rebuilt motor and trans
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Could be.

Do you top off your tank? Meaning, after the click, do you continue adding gas to get to your desired dollar number?

Separately, have you verified fuel pressure?
 

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Discussion Starter · #3 ·
The gas gauge doesn’t work so I was just checking if it had gas. First time the nozzle clicked I quit filling. Hadn’t checked fuel pressure but new fuel pump in October
 

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‘01 Silverado 2500HD 8.1/Allison 5sp xcab long bed
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And, what truck are you talking about, Steve?
 

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2000 Silverado Z71 4x4 5.3L 480k+ miles w/ GM rebuilt motor and trans
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OK... That's a complete reorient of my brain. o_O

I would not think the fuel leak is related to the vehicle dying. Was your leak out of the top of the fill spout or the neck beneath the fuel spout? Could be something was damaged during the fuel pump install and finally was noticed or failed.

If it's dying every time you come to a stop, I'd say it sounds to me like a vacuum leak in the brake booster.
 

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Don't rule out the possibility of a bad ground from the engine to the frame. My son was fighting the same condition on his '02 Escalade with a 6.0L and it turned out to be a frayed ground wire from the rear of the passenger side head to the fire wall. Replaced it and he was good to go...
 

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Discussion Starter · #10 ·
Yes GMTG. I move it to neutral at a red light. Then I’ll feather the gas and it keep running with my right foot and my left on the brake. I found a booster on Rock Auto. Thinking of trying that.
 

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Sierra 2500HD 4x4 8.1Vortec w/Ally tranny
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The gas gauge doesn’t work so I was just checking if it had gas. First time the nozzle clicked I quit filling. Hadn’t checked fuel pressure but new fuel pump in October
When it runs inbetween stalling, does it run well? Have you run an ODB2 scanner to see if there’s any codes?
 

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Sierra 2500HD 4x4 8.1Vortec w/Ally tranny
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When it runs inbetween stalling, does it run well? Have you run an ODB2 scanner to see if there’s any codes?
when it’s in park, with the engine running (if it will idle) try wiggling the pigtail that connects to the Throttle Positioning Sensor. If the idles changes, your pigtail probably needs replacement.

many ‘02 8.1 Sierra is not throwing any codes, but I know my TPS is going out on me. It doesn’t stall, but does the opposite- I’ll be cruising and can take my foot off the gas as if I were using cruise control, and it keeps spitting gas. Sometimes I’ll have my foot on lightly and without ny doing it accelerates for a split second- like a hiccup and then spits fuel.

did your mechanic test the throttle body, the fuel pressure, the fuel injectors, the coils, TPS, etc?
 

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A mechanic had it for a month and couldn’t fine vac leaks. I drove it to day and it consistently died at every light. I stopped and topped off the tank(6gals) and when I got home gas was dripping out of the gas filler at the cap when the truck was in the sun 90 degrees here today. Could this two problems be related?
Take a can of carb cleaner or brake clean with the truck idling spray the cleaner around the engine slowly in spurts trying not to spray it directly into the intake, if your idle changes it's definitely a vacuum leak. If that's not it then my guess is tps is going bad.
 

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2000 Silverado Z71 4x4 5.3L 480k+ miles w/ GM rebuilt motor and trans
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Take a can of carb cleaner or brake clean with the truck idling spray the cleaner around the engine slowly in spurts trying not to spray it directly into the intake, if your idle changes it's definitely a vacuum leak. If that's not it then my guess is tps is going bad.
Don't do that with carb cleaner if you like your valve cover paint. 😬
 

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‘01 Silverado 2500HD 8.1/Allison 5sp xcab long bed
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For the random reader, the truck in this thread is an ‘88 which came with OBD1 technology. OBD2 came in 1996.
 
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