'93 FD, manual:

Not sure how to describe this other than "jerky" when getting gently on throttle, and when letting off throttle. It feels "loose".

Pretty sure its not the 3k hesitation, because if I go off throttle while still in gear it does this jerking front-to-back 3 or 4 times before smoothing out.

Here is a specific example: 2nd gear @ 30pmh on a residential street, approaching a stop sign I let off the throttle completely... jerk front to back a few times. If I clutch, it stops doing this. If I add throttle gently it does the jerkiness a few more times. If I add throttle hard then no jerk.

I thought it might be bad diff mounts, but they checked out okay. What else could it be? PPF? Or is this normal for the FD?

(I've had this particular FD for a year now. I haven't had a new FD since 1994, and I just don't remember if it did this jerk thing back then.)

Thanks.

 

Has this become worse at all, or is it the same since you got the car?

Is there any chance the kicking is tied to your foot being bounced a bit against the throttle?

David

 

That is def not normal..have you checked your PPF?

 

Its def not my foot bouncing the throttle -- my foot will be on the floor. Its not "kicking/bucking" from the motor; it seems down the line from the motor, somewhere between the clutch and the wheels. Its a "rocking" feeling. Imagine sitting in a secretary chair, leaning back, and bob your head a couple times... you'll experience a similar sensation to what this car is doing. But if I stomp the throttle hard its just strong, no bouncy... only @ low RPM when I'm going gentle does it "bounce". (Its like the car only wants to go hard and fast all the time.)

I've had this particular car for 1 year and it doesn't seem to be getting worse IMO. Like I said, IDK if this is just how the FD is.

I have thought of the PPF but not really sure how to easily check it. I suppose I could just spring the cash for a reinforced new one and hope thats it, but thats not super cheap either. (Maybe I'd just do that next time it needs a clutch).

 

Sounds a lot like the rear differential to me. Limited slips can be a bit aggressive at times and when letting off the throttle you may feel the car want to instantly decelerate, or when getting on the throttle the car may seem eager to go. I would recommend changing your differential fluid and possibly considering a heavier weight.

 

If it's the PPF you'll usually also see the shifter moving significantly.

Excess backlash in the differential is another possibility. It wouldn't be a waste of time to change the diff oil, remove the cover, and inspect the gears for excess wear.

David

 

My car had the exact same issues when the tune was too lean at low rpm cruise, I had bucking at light throttle/low rpm and bucking on decel. Same deal as you, more throttle or clutch in and the symptoms would go away. Is your stock or does it have fuel mods/ecu?