2005 gmc 1500 5.3 z-71

[barry1982]

Good Afternoon Gentlemen, I am having a problem with my truck, and hopefully someone on here can point me in the right direction.
Strangest thing, truck starts and runs smooth,no problem. After driving on the highway for a while, it just stops. No bucking, just like you turned the key off.
Try to restart....no go. Cranks, but won't fire. Let the truck set for 10 min or so, and fires right up. Sometimes I can go for miles before it does it again, sometimes 20 feet. Obviously has fuel pressure, or it wouldn't start/run. No codes coming up on dash. Pulled off intake manifold, and changed out cam position sensor. Didn't help. Maybe crank position sensor? Anyone have any experience with this? The closest GM dealer is over an hour away.... don't trust it to go that far.

[4x4k30]

Originally Posted by barry1982

Good Afternoon Gentlemen, I am having a problem with my truck, and hopefully someone on here can point me in the right direction.
Strangest thing, truck starts and runs smooth,no problem. After driving on the highway for a while, it just stops. No bucking, just like you turned the key off.
Try to restart....no go. Cranks, but won't fire. Let the truck set for 10 min or so, and fires right up. Sometimes I can go for miles before it does it again, sometimes 20 feet. Obviously has fuel pressure, or it wouldn't start/run. No codes coming up on dash. Pulled off intake manifold, and changed out cam position sensor. Didn't help. Maybe crank position sensor? Anyone have any experience with this? The closest GM dealer is over an hour away.... don't trust it to go that far.

try unhooking the maf sensor and drive it for awhile my 07 6.0 has a problem like you are talking about I just unhooked the maf and mine runs good but there is a problem some where that will need work soon its worth a try

[barry1982]

Thanks 4x4k30..... will give that a try. Can't hurt at this point. I heard you can test the map sensor as long as the truck will run. If truck is idling, unplug map sensor. If truck dies....map sensor good. If truck keeps running....map sensor bad. Don't know if it's true....but read it some where. Also picking up a gauge to test fuel rail pressure. Guess it's supposed to be around 50 PSI if pump,lines are okay.

[determined]

Exact same symptoms my wife's truck had as the fuel pump was giving up, nursed it for 40 miles, shut down, restart, go for a bit, repeat until it finally died for good.

Towed it the last 5 miles to home and changed the pump out.

No problems since.

[barry1982]

Thanks determined.... did you change the pump, or did you take it in? I heard it's not a great job, and of course my tank is full..... Heard some guys lift the box rather than dropping tank.

[95 S_Trucker]

Before you start replacing parts, lets try and figure out whats happening.

Did you use a fuel pressure gauge to verify fuel pressure?

Does it have spark when it doesn't start?

[barry1982]

Hi 95 S...... I am actually picking up a fuel pressure gauge tonight. Will start truck and test pressure. The truck has 100000 miles...so would not be surprised if the pump is weak. As for spark, not sure.. it has only quit when I'm out on the road without tools. Seems to restart after 10 min or so, and gets me back home. I am also alone, so tough to test for spark and turn truck over at the same time. Might have to round up a helper.....

[barry1982]

Update: I tested the fuel pressure... and it's great holding at almost 60 PSI.
Cleaned the Mass Air sensor with Mass air sensor cleaner. Started truck, and let idle until temp was approx. 1/4 on gauge. The truck ran good cold, but once it warmed up, stopped again. Will not start. Seems to only start cold. Fuel pressure remained at 60 even after it stopped.
Plugged in code reader, got a stored code P0171. (lean) . That's where I'm at Gentlemen. Any ideas?