I have searched but did not find the same situation pop up.

1999 2500 4x4 5.9L gas engine with 174K. When warm, never when cold, if I put truck in reverse and don't press on the gas, all is fine. If I step on the gas, the truck will sputter and buck and backfire and lope like it is running rich or it will just die. NEVER does when cold. Not throwing a code, according to 2 mechanics. Plenum was done around 120K and rebuilt tranny then too. What has been done:

new plugs, cap, rotor, wires.
new IAC
all O2 sensors checked, including unplugging them and it still would die

Last night when hauling horse and trailer, when I pulled off highway on an exit ramp at the stop sign it died. Immediately restarted. slowed to a stop just down the road to turn, it died. Then it did not do it again.

Mechanics are stumped. I am stumped. And my wife is going to want to use the truck to pull horse trailer, so issue has to be fixed.

Any ideas?

Roger

 

Clean the throttle body. Pay special attention to IAC well.

What brand IAC? Not like I have never gotten a bad part right out of the box......

 

Okay. Will give that a try on the throttle body. I believe the IAC came from NAPA but don't know what specific brand it was.

Thoughts on why it only happens when warm?

 

Parts change shape with temp. It's possible that once warm, there is either an electrical issue, or a mechanical issue with it. (either a coil opens, or shorts, or something jams...)

 

if getting the truck to run right is priority #1 and money is no object, replace throttle position sensor (TPS), drivers side of throttle body. about $40-50 at local parts store. save all old parts that don't solve the problem as spares for the future.

 

my stalling in reverse was due to the crank sensor on top of the bell housing. I swapped IAC's, TPS, pre cat o2 sensor, cleaned TB, checked grounds, and probably missing a thing or two, and it came down to the crank sensor. I did things one at a time to find out what cured it so I know for sure what the problem was.

just figured i'd throw my problem/cure out there for ya.


edit..... and to add to my statement, my problem was only when the truck was warm. anything over the 130 temp mark.. never did it under 130 mark....

 

xplorer82 is the winner!!! It was the crank sensor. The last time a crank sensor went out on me, the truck would not start at all. But, problem solved!

Roger

 

Glad to hear you got it fixed. Thanks for updating the thread as well.

 

No prob. I hate that when folks don't say what fixed it.

 

Cool beans man. This should help other folks that might happen to run up on your thread later down the road.