Bucking
 

I have a 1994 SSEI..and in the last week when I get to the speed of 38-45 the car is acting like its bucking...checked transmission fluid levels and was full...was wondering if there is a sensor for the overdrive or what may cause this. In the past once inwhile it would also do it at 55 to speed of 65....almost like a hesitation.. Any suggestions on what to check would be great and all help is appreciated.

Moved to '92 - '99 section. It will get noticed more here ;)

Inan NA I would suggest a tuneup as thats normally the cause, not sure in a SC'd car so I'll be watching this thread.

I seem to have the same problem with my '92 SE I think...

Only happens to me in D that I've noticed, and it's when I'm holding my foot on throttle just enough to go around 40 without speeding up or slowing down, and the car feels like it's shifting in and out of a gear...

Is that about what your's does?

Yes thats what mine does also..........any suggestions as to what can be done?

I'm stumped too, just never really remembered to ask about the problem myself. Whenever my car stats doing it, I just bump the speed up so it stops. So my assumption would be transmission that can't make up its mind.

Don't take my word for it though, I'd wait for the gearheads to skim over this and ask more questions.

One thing that could be checked is the TPS, also the vacuum going to the modulator. Look for any trans fluid in that line. Then I'd consider if this is what is known as chuggle and look to a tune up.

Next time it starts to buck, tap the brake pedal just enough to light the brake lights. If the bucking stops, then I think it's your torque lock sensor in the transmision. At least that is what I have learned about my wifes 2000 GP GT that does the same thing. Tranmisions starting around (1990?) were designed to lock at a certain speed, eliminating any slip that was in the prior designs. I think your sensor is just switching back and forth between lock and un-lock. It is designed to disengage whenever the brake is applied.
(Sorry for any mis-spelled words, I wish there a was spell check on here! )

also a good thing to check is the coil pack.. and fuel pump.. My 91 century did that alot on WOT changed the coil pack and pump it stopped.

We aren't running WOT, just keeping the throttle down enough to run at around 40.