Hey all, as of the last few months I've experienced my cars rpms fluctuate when she's coasting around 50mph, with the jerking too. Wonder what could be causing it and where I should start to diagnose the problem. I've got a 305tpi paired with the 700r4 (both original from 1986)

 

Do you experience this when going uphill in 4th? Or when trying to pass someone on the interstate? Does it idle smoothly? Or does this only happen when coasting?

 

only while coasting, she does have a rough idle in the sense that the car shakes, the rpms are steady though.

 

Maybe the TPS

 

possibly, ive heard it could be something to do with the torque converter lockup. I do have an automatic transmission...