Engine/Transmission (1994 - 1998) Truck bucking at 40@60

[TravisG]

Alright, I am at a loss here. Driving the truck over the last few days at about 55 mph the truck starts to buck or surge. I have a fuel pressure gauge and all that is fine. The turbo is not surging or at least it is not showing it on the boost gauge. This has never happened before. I thought I got a bad tank of fuel, so I changed the filter, and added a can of Diesel 911. Still doing it. I checked the codes and all I am getting is code 12 which I think is no codes right. I need some help here. Also, I just got a new TPS about a month ago, and I cleaned it just the other day. Could it be the transmission temp sensor? I am not sure if it is in the pan or not on a 97 or maybe a solenoid. Sorry this is so long, but I can't figure it out. Thanks in advance.

 

[Woodenhead]

My truck's been surging at lower speeds as well. It got much worse when I had my throttle cable recal done. In my case I think it's the week throttle spring because it all starts when I hit a bump and my foot moves then the truck surges for a second causing the foot to move again and next thing you know it get's pretty jerky. If I take my foot off, let it settle down and then throttle up again it's fine. After reading some TDR posts I bought a pack of throttle return springs the other day at Schucks and plan it install some heavier ones this weekend.



Not sure if this is the same problem you having or not.



Mike

 

[TravisG]

Thanks woodenhead, I will look into that, but I think this is an internal thing, I haven't noticed if it does this while I am going over bumps or not. If anyone has any other suggestions, I am open to anything.

 

[TravisG]

Nothing Huh. Any suggestions or shots in the dark would be appreciatedc

 

[Woodenhead]

I put the stiffer throttle return spring in yesterday and my problems are solved. It's amazing how much difference the spring made.



Could be a problem with you GSK. When I put my 3kGSK in it tended to hunt or surge around 1200RPM which caused some bucking at lower speeds. I needed to do some adjustments on the springs. The first adjustment I made just moved the problem to a different RPM. I ended up only adjusting one spring to get the problem cured. Put your truck in neutral and slowly rev the motor to the RPM you would be running at the speed you're having problems at. Can you easily control hold the RPM steady there or does it start to slowly speed up on it's own?



Mike

 

[BobS]

On a cold afternoon after sitting all day, my truck also shudders between 30-50 on initial acceleration. I simply let off the pedal some and restart slower and the shudder disappears. I am convinced it is a temperature sensor somewhere that is not happy with the cold.