Any of you guys seen this problem. I've got a stock '84 SE with 70K miles on a rebuilt 13B (170K miles total on the car); it runs great except for one minor problem: in 1st or 2nd gear if I try to maintain a steady slow speed (like in a parking lot) the car bucks along as if I'm quickly tapping and releasing the accelerator. The RPM is rock solid during all this so I know it isnt the engine surging. Once I get above about 25mph or in the other gears I dont notice any problems maintaining a constant speed.

Any thoughts?

 

A lot of 1st Gens. have this "shuddering" problem in reverse or 1st gear, but I've never heard of this problem at the speed you mention, or in 2nd gear.

Wish I could be more helpful.

 

Slop in the motor mounts, tranny mount, u-joints, and differential. Basically, anywhere in the driveline, if there's slop then you'll have that bucking. Check tranny mount 1st.

 

Its pretty common.The bucking is exacerbated if you install a light flywheel.This leads me to believe it has something to do with rotaries lack of low end torque.Driveline slop will make it worse if your rearend/trans is loose/old.

An engine torque brace might help.I like RB's unit,its simple,cheap and strong.After installing it,my 1st gear and Rev shudder was completely eliminated.Cant say if itll help with the bucking,my car hasent exibited that behavior since it had a 12A,nearly 7 years ago.

 

I agree. A lightweight flywheel will be less forgiving at low rpms. I've noticed it myself.

 

I had that exact prob man. Check your timing as well and your carb man. My car bucked bad. It is SP and bucked hardcore. Had a lightweight FW too. HAD. I'm not going into it. But anyways check your timing.