You say the vibration is not noticable at idle. Is that with the tranny in Park or in gear.

I would first have the engine mounts, engine shocks, and tranny mount inspected.

You can also move the linkage by hand while the engine is running and in park.

You may also have a bit of fuel starvation. How are the filters? Air filter can be dirty also.

Do you notice any smoke when the vibration occurs?

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 TD Turbo, chipped. Still needs EGR Delete, 228K

90 Dodge D250 5.9 Cummins/5 speed. 400K