BajaRunner

Usually when Im in 1st or 2nd gear, and am traveling slowish, and I pull my foot off the gas pedal, the truck will buck/jerk really quick, and it feels like I am putting the brake on, but not.

This is a manual transmission, 22re, etc. What the heck is that all about? It sort of startles me when I don't anticipate it.

A7QG59F2

My first two trucks did this (4cyl). Once I got my first 3vze (before I knew that I should have taken my truck to the junkyard before putting that stupid engine in) it didn't do it as much. I always assumed it was the engine slowing down faster than the truck, then catching back up to the speed of the truck, then slowing down again, etc. etc. etc. untill the drivetrain and engine can both agree on a speed...

mightymouse

iTrader: (6)

two things to check here if i was you. Throttle damper thingy that stops the throttle from closing too fast and tps. Honestly sounds like the tps is out of wack.

BajaRunner

Yeah Mighty Mouse, thats what I thought. The dampener is set correctly from what I can tell, as well as the TPS being set (and its brand new).

Its much more noticeable when I have the AC on. Like I take my foot off, and the compressor just grabs all the residual power from the crank and really slows down the truck.

Ok it sounds like this is a common issue. I've checkd that darn TPS too many times.

mightymouse

iTrader: (6)

If the tps checks out and the damper is good it sounds like the vaccum from the brake booster is cutting the fuel to quick. mine did that before it burned down. Check the brake booster that's my next step of advice.

BajaRunner

But I don't hit the brakes when this happens. It just does it when I release the gas pedal, and it FEELS like I'm slamming the brakes. Are you saying the two are related I guess.

How would I test the brake booster?

/me goes and looks at FSM...

mightymouse

iTrader: (6)

my vote is still for the tps though. On mine it was like every thing worked just right but it was adjusted a little too far and the idle switch on the tps was burnt out or the contact was gone.

rattlewagon

My runner doeas this also. Ill be going down the highway, and take my foot most of the way off the gas, and it kinda cuts out, then comes back on, just as you described. Ill be checking my TPS and watching this thread.

BajaRunner

The whole TPS thing is weird to me:

1) My TPS is brand new, and I have it set at .88 mm to go to infinite.
2) I have checked voltages at the ECU, and they are in spec
3) When I disconnect my TPS, the engine smooths out a ton at idle, and drives better. (I know this has something to do with it dumping fuel).

I feel the problem might be related

mightymouse

iTrader: (6)

my tps was set proper as well and did the same thing. Funny thing was it started when i replaced the tps not before. I replaced the old one due to other problems and chasing a motor bug "gremlin". Also check the afm flapper as it might be closing too fast and giving the result of the motor cutting or bogging when the throttle is off.

DanStew

I have the same issue. if i just take the foot off the throttle it seems to do it. I adjusted my TPS to specs. Havnt touched the throttle dampner. I was wondering it was the deeper gears i have installed. I have 4.88s in and i was thinknig it was engine braking. I am subrscribed to this one.