My truck started bucking when I hit higher speeds around 70 mph. I took it to a diesel mechanic and they said the converted was clicking on and off very fast that's the cause for the bucking/jerking feeling. They rebuilt transmission and replaced converter. I just got the truck back three weeks ago and didn't have a problem. I went on highway and drove about 80 mph for about 10 miles. No problems. I topped off the rest of my tank at Hess and as soon as I went on the turnpike it started again. The engine is loud as normal and right when it jerks the engine gets real quiet. The rpms drop very slightly. No check engine light. The feeling is almost like if you step on the gas hard and stay on for a little then let go and jump on it again. It's like a bucking feeling is the best I can describe it as. I've asked a lot of people and no one seems to know. Any help would be greatly appreciated. I'll give more information if you need it. Thanks.

 

I just bought a 1998 this week and it's doing the same thing it comes and goes talked to the guy I bought it from he said there is a sensor he replaced last time it did it but can't remember the name of the sensor.

 

Their is a Throttle Position Sensor that can cause this issue, but my issue with my TC was a simple ground on the battery.. But you can re learn your TPS if you disconnect the batts, turn the KOEO. Let it sit for 3o min then turn the key off and replace batt cables then turn KOEO and slowly depress the throttle and slowly release it... and see if it helps.

 

I'm new to the cummins diesel this is my first one so I'm kinda lost on what KOEO is

 

When my truck jerks I have no power at all. My foot is on the gas all the way to the floor and it won't go. After a few seconds it comes back to life for a little until the next jerk. Did the key thing and the only code its reading is p 1693 which I know is no help. How do I find the other codes?

 

1693 means there is more codes and you will have to hook it up to a scanner to pull them. If you don't have a scanner many of the auto parts stores will let you borrow one. If you have a fuel pressure gauge, what is your fuel psi when it bucks?

 

I went to Advanced Auto today and had codes read. The only code that was on my truck was a P0234 - Turbo Boost Limit Exceeded. I have a chip on my truck, so I was thinking that the chip was producing too much power. I disconnected the chip, so the truck is pretty much stock now. The only other thing the guy before me did was put on a better turbo. I don't have a fuel pressure gauge on my truck, so I am unable to tell you what the fuel psi is. I took it on the highway after disconnecting it. The truck was fine pretty much the whole time. I hit the gas going around 80-90 mph. It bucked about four times, but they were as severe bucks as before. Any ideas?

 

Possible lack of fuel problem. Are you running a stock lift pump? You really need to get a fuel pressure gauge on it. Does it do it at low speeds or just when accelerating at high speeds?

 

It only really happens running at high speeds. I need to get one, but not really sure how to hook it up. Might just have someone install it on it for me.

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The jerks weren't* as severe as when i had the chip connected.

 

KOEO is Key On Engine Off.