jerking and bucking on deceleration

[fatt_owl2.9]

This has been a problem with my truck since I bought it almost a year and a half ago. I've mostly ignored it because otherwise my truck has always run great and been reliable as hell. But now it's starting to irritate the **** out of me.

Under acceleration my truck is great...smooth, strong power, no hesitation. But letting off the gas at say, 55 mph, or any speed really, the engine will not smoothly decelerate, it is always a herky-jerky motion, like the clutch is bouncing off the flywheel or something. That's really the only way I can think of to describe it. If I'm at a dead stop on a flat road and I let the clutch out without giving it any gas, it will take off smoothly for about 2 seconds and then start the herky-jerky thing again. It's caused me to form what I think is probably a bad habit, any time I have to slow down in traffic or slow down to make say...a right turn, instead of downshifting and slowing down, I just put the clutch in and coast smoothly for certain distances, because I can't stand the bucking, it's really infuriating. I'm sure this is putting a little extra wear on my clutch components.

I would really think this isn't a fuel delivery issue of some kind, but maybe a driveline issue? I really don't know. Is there a throttle position sensor or something that could be causing problems? Throttle tip-in can sometimes be slightly abrupt. But again, acceleration is always smooth and normal. Thanks for any advice guys.

 

[Big Jim M]

First guess is your clutch springs have gone away. I never use the engine to slow a small vehicle. I leave it in High until it reaches near the idle speed of that gear and then use the clutch.
Big JIm

 

[tnt4me]

air bypass valve is my opinion. Mine was clogged and would not "help" get the exhaust out the tailpipe and gave me the jerks....