LennyK

Thanks for the reply,

The hesitation stops as soon as I let of the gas, or if I floor it to reach that 60mph speed. The car seem to idle fine, no known vibration that i can tell, related to tires.

thanks

-L

is the engine stumbling or cutting out?,

meaning does it do it only when you are on the gas at 40mph or does it do it when you are off the gas as well (coasting)

or is the car shaking all together when that speed is reached? (non engine related)

if it shakes  when the car reaches that speed on any occasion  these are the things to check for..

Wheel balancing

Alignment

Tire condition

Suspension condition (ie...ball joints, struts, ect....)

←

I seem to have this really odd problem with my LS400. While accelerating at the speed of between 40-60 mile range, the car consistently hesitates, hestation turns into forward shaking. It always goes away when the speed reaches 60, and does not start again untill you get back to 40MPH again.

Anyone has any ideas as to what the issue may be. Thanks in advance