well, maybe, but why doesnt it vibrate when it is cold if it is the motor mounts?

i was going to suggest the engine is missing. to check that you need to (carefully) pull each spark plug wire off and see if one doesnt slow the motor down. if you find one that doesnt you have found your miss.

then if you find a miss, first check the plug. replace it.

if that doesn t do it check the plug wire by changing it with one that is known to be good.

after that i would check the fuel injectors by switching them around.

and finally it might be a burnt valve i suppose which will get worse when it is hot and the valve is longer, though with hydraulic adjusters this may not apply.

any of these things is a lot simpler than just changing the mounts if you arent for sure that they are bad.

good luck

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.