stalling engine

[HOME WORKS]

First things first. My truck is a 97 with a 6.5 with 178,000 miles.
The problem is the engine stalls as if running out of fuel, sometimes as much as 10 times a day (25 to 50 miles daily)Sometimes
it will run fine all day. This has been going on for about the last 1500 miles. It will happen at idle, at cruising speeds or while accelerating but not before reaching operating temps. When it stalls I can shift to neutral and it will restart on the first try.
I just had the lift pump and fuel filter replaced
this week and still have the problem.
I have owned the truck since 110,000 miles and know the injector pump was replaced prior to my
buying the truck.
The GM mechanic has no idea what the problem is since there are no codes.
Has anyone experienced these symptons and what was the problem?
David

[charliepeterson]

If you go to the top of this page and hit "search" and type in "stalling" all your questions can be answered.
This stalling issue sounds very much like a failling PMD/FSD. This is the small black box on the side of the Injection Pump. Driving along it's like someone turned the key off right? No codes will ever show up when this goes South.


Good Luck

[dslpwr]

Dont over look oil presure switch.
It does strange things also.

[dilemma]

I'm having the same trouble "again"(96 k1500 135,000 mi with 3rd injection pump". Replaced PMD last November due to the same symptoms. Seemed to fix the stalling trouble instantly but did little for the hesitation between 46-55. Remote mounted new PMD with the aluminum heat sink hoping to improve durability. No luck. Seems to get worse in hot weather. Here goes another $400 and a good weekend. What a piece of junk!!!

[sabburch]

If oil pressure switch goes out, it drops the voltage to the lift pump and it starves the motor for fuel. I would check that first.

[ucdavis]

Dilema's sounds like lift pump while Home Works sounds like fsd. If you are "missing" at high revs only, it can be fuel starvation. IP generates enough suction to get by drawing fuel thru ift pump from tank, but not enough to run well under all fuel demand situations.
Click on Members Area @ top of page, scroll down to Reference & read about stalling there. Good checklist including both FSD & lift pump checks.

[HOME WORKS]

Thanks for the responses. I went back to the dealers service manager and showed him the info about the FSD as per charliepetersons suggestion.
He was already aware that this is the most common reason for my problem and agreed to change the FSD and if the problem still exists after 2 weeks then he will remove the new part and re-install the old one at no charge to me. Seems to be very fair and if that is the problem then it saves me the cost of a IP.
The truck will be back to the dealer on thursday for the FSD replacement.
I'll keep you informed.
David

[Kennedy]

If it restarts cleanly after sitting and cooling, it is not lift pump related. While an inop lift pump IS often a contributing factor, an air lock will not instantly bleed itself.

As stated above a miss under load sounds more like a lift pump. Lack of lift and return fuel causes the PMD to heat up and fail quicker.

[HOME WORKS]

It's been over a week now with the new FSD and everything is great. The engine has not stalled one time and seems to have more power than ever.
I guess I will put a set of new tires on it and keep it another year.
Thanks for the advise charlie.
David

[ryno]

Hey Home Works,
Did the PDM fix your problem perminatly? I have just replaced the injection pump, PDM, lift pump and fuel filter. My truck 1000km's later has begun acting just like yours. Mabey my new PDM is toast already? If you see this post please let me know, or anybody eles whom has had this problem.

[HOME WORKS]

RYNO,
It's been a few weeks and few tanks of fuel and still running fine except the starter went out a couple days ago.
Three times in the shop in 2 months is not good. Sure makes a new truck more desirable, just hope it can make another year.