Engine violent bucking and loss of power?

Ok if the coolant temp sensor is bad then you do need to replace it. I am not saying it will fix all you problems but it will make it so we can run tests and be acurate if nothing else. See the coolant temp sensor tells the computer how warm the engine is, by doing this the computer then can help compensate for fuel mixture and timing adjustments and shift points and when it shifts and when it can go into OD. So if this is know to be bad then replace it see what it does and if it still acts up then we can do some other tests to figure out the rest of the problem.

The only way that could cause a loss of power is if it gets extremely hot. If it's not, that's not the cause. You might need to get your catalytic converter checked. If it stops up, your engine can't breathe and therefore, loses power. Also, check fuel pressure/volume. Lack of fuel will cause loss of power as well.

Check the fuel pressure /charcoal canister purge solenoid.