been having a knocking sound coming from the rear of the motor i can feel it in the gas pedal and brake pedal when coasting between 20-35 mph you can also feel in the floor i have changed both belts (engine and sc) i have ruled out the motor and pulleys any advice will help

rear of the motor compartment i have an 02 ssei

Have you checked out the trans/engine mounts???

If its on maybe the right or left side a bit, I would suspect a halfshaft, but of course you would end up with clicking on turns.

Can you tell if it'* RPM or speed related? That will help narrow down the cause.

the sound is on the passenger side it really only happens from 20-35 it mostly goes away when i accelerate it vibrates the floor board when i am coasting

Check the front suspension for loose front end parts... Really bad tie rods and bearings will do that (normally on Chrysler vans)

Under load while accel, the bad toe angle puts the loose tie rod under load and keeps it from moving too much, let off the accel, then its the road turn which dictates how straight the tires are. Normally the tires will move back and forth a bit and cause the tie rod to knock around.

Check for loose stab links and blown strut mounts or loose strut to knuckle mounting bolts as well.

Axles is the next thing I would look at. When you turn pretty decently, under all the conditions you described, is the noise and vibration the same???

the noise does not happen under accel i took it out on a back road with no one around for miles lanched from a dig and it made no noise (car wasnt heated up all the way) turned around rolled at 25 car fully warmed up and the noise started did the launch to see if it was accel related thinking from other post maybe tie rod issue bearings look fine and i dont have the hummmm like i had with my old bonnie it sounds like cards in a bike wheel

That kind of noise is typically more normal to be a CV getting loose and clunking around in the outter shell. Try a slow wheels locked in one direction turn in a parking lot. Then try the other side. Any clicking, noises, feeling?