Stalling Under Throttle

[RlySlow]

Hey all,

Put this in my intro thread but figure more people might actually see it here.

Having an issue with my 97 k1500 5.7 truck.
Started last week but has gotten a lot worse.
Most commonly does it under heavy/full throttle but now last couple days is doing it at low throttle too at times.

Commonly if I go full throttle - it'll stall, go, stall, go. If I do it from a stop and it stalls I have to restart the truck. We're dealing with some nasty heat & humidity right now so I'm wondering if that's affecting it. This morning it was stall/go/stall/go from only like 10-15% throttle. Did it about 8 times before it came out of it and let me get up to 35mph.

I was thinking maybe TPS? I do already have a set of plugs & wires & o2 sensor to do this weekend.
I've already had a CEL due to O2 but I'm going on my lunch break to the advance here to pull codes and see if I have anything new that could be related.

Here's a video of it doing it at full throttle:

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[chipskittles]

Distributor/ICM

 

[RlySlow]

Distributor/ICM

I'll have to look into that for sure..

I pulled the codes @ Advance. Nothing besides the o2 sensor.

I also might check fuel pressure - it has had a lazy start ever since I've had it even with a new battery/new starter. Fuel sending unit is bad anyway so wouldn't mind replacing it.

Just don't want to throw parts at it without gaining anything.

 

[RlySlow]

So I was checking fuel pressure.
First time turning key on with engine off - it was only 35psi.
Was fine under cranking at 55-60psi.

Idle was fine. After initial prime & startup every time I checked it with key on engine off it was at the 50-60psi it should of been.

Then driving it with gauge under my windshield wipers so I could see it - I floored it and it'd drop to 40psi and stall out constantly.
Then it got so bad now on the way back home slight throttle from any stop and it'd completely stall and I'd have to restart it every time when it stalled it'd drop to 40.

So does it sound like a fuel issue to anyone? I just don't want to throw parts at it unless I know.

 

[AllThrottleNoBottle]

So I was checking fuel pressure.
First time turning key on with engine off - it was only 35psi.
Was fine under cranking at 55-60psi.

Idle was fine. After initial prime & startup every time I checked it with key on engine off it was at the 50-60psi it should of been.

Then driving it with gauge under my windshield wipers so I could see it - I floored it and it'd drop to 40psi and stall out constantly.
Then it got so bad now on the way back home slight throttle from any stop and it'd completely stall and I'd have to restart it every time when it stalled it'd drop to 40.

So does it sound like a fuel issue to anyone? I just don't want to throw parts at it unless I know.

Yep, that definitely sounds fuel related. Combined with the lazy start (another sign of pump going into retirement in my experience), sounds like the pump. Might wanna change the fuel filter for ***** and giggles...it needs to go with a pump change, anyways. Anyhow, 40psi and down you should definitely have your issue.

Rich

 

[RlySlow]

well it's $50 for a fuel pump & whole sending unit assembly on Rockauto. so I think I'll go ahead and just replace it. it'll fix my fuel gauge at minimum, and i'll do fuel filter along the way. If it doesn't fix it I'll look at other options but since Im sure it's still needed I won't feel like I'm completely wasting money throwing parts at it yet.

 

[AllThrottleNoBottle]

well it's $50 for a fuel pump & whole sending unit assembly on Rockauto. so I think I'll go ahead and just replace it. it'll fix my fuel gauge at minimum, and i'll do fuel filter along the way. If it doesn't fix it I'll look at other options but since Im sure it's still needed I won't feel like I'm completely wasting money throwing parts at it yet.

That's true, no doubt. Hey, I really would recommend against the 'Special of the day' econo pumps...I've seen a lot of them die a year or so out, or just plain suck (no pun intended) out of the box as far as pressure goes. The Delphi is the only way to go...yep, it's a hell of a lot more, probably $130'ish, but its 100% and you ain't gotta drop the tank but once.

Just my $0.02...sometimes worth considerably less.

 

[Keepinitoldskool]

That's true, no doubt. Hey, I really would recommend against the 'Special of the day' econo pumps...I've seen a lot of them die a year or so out, or just plain suck (no pun intended) out of the box as far as pressure goes. The Delphi is the only way to go...yep, it's a hell of a lot more, probably $130'ish, but its 100% and you ain't gotta drop the tank but once.

Just my $0.02...sometimes worth considerably less.

And definitely stay away from Airtex pumps. Customer supplied one and right out of the box it was bad, of course i didnt find out till after i put it all back together and tried to start it. He took it and swapped it out for another one and less than a month later it **** the bed too.

Sent from my SAMSUNG-SM-G890A using Tapatalk

 

[RlySlow]

Point taken - ordered a delphi pump for her along with new fuel filter.
Also plugs/wires/air filter. Figure I'll just do all the maintenance stuff at the same time. Hoping after this downtime I don't have to worry about much on it for awhile. Just rebuilt the entire front end with all moog goods a month ago and new tires, new door pins, tailgate hardware, new all terrains, new 4x4 switch, fixed ac, new blower motor actuator and blower resistor. List goes on. Just ready for this thing to be a nice dd.

 

[97Sierra4x4]

I believe I am having the same problem in my 97 GMC k1500. Felt like maybe a trans problem but I had it in neutral and tried to rev the engine and it would just stutter and stall out. it only happens once in awhile and it gets more frequent when it is hot and humid out. I just replaced the lower intake gasket, new starter, and brand new exhaust (manifolds to magnaflow cats/cat back system). I thought I had the problem solved with new exhaust because the old cats were plugged but then the problem came back. does anyone on here think I could be having the same problem? I'm really hoping it's fuel related and not the trans!