I have a 1990 Nissan Stanza manual 5 speed that runs normally the majority of the time, but sometimes something gets messed up and it won't let the RPMs get up to normal. When it gets in that condition it revs up and drops down, revs up and drops down. This causes a bucking behavior when trying to accelerate while shifting gears after having slowed down to make a turn. It will accelerate a little, then start the bucking. When I hold in the clutch and try to rev it up that's when it does the rev up and drop down but during those times it never revs up very high. While it's in normal condition after making a turn and going through the gears to accelerate after shifting to each successive gear, it will accelerate sort of slowly then at a certain point it feels like something kicks in and it begins to accelerate more rapidly. When the problem is occurring, after shifting gears it will accelerate sort of slowly, then when it should begin to accelerate more rapidly instead it begins the bucking behavior. What seems to bring on the problem condition is when I use the motor to slow down, not downshifting but just letting off the gas pedal. It's like the back pressure (or whatever) engages the problem.

When I turn off the ignition and start the car again the problem is gone instantly no matter how quickly I do that. I've had this car for many years and it has only recently started this sort of behavior. Does this sound familiar to anyone?

Thank you for any help!

David
Maine, USA