I just changed my water pump and timing belt.
Everything was aligned ( took it apart twice). Now the car runs perfectly however right around 3500 RPM before it changes gears the engine vibrates causes a noise. The noise is felt inside the car ( The dash starts vibrating).
Can anyone tell me what could be wrong ?
Could an improperly put in motor mount cause the symptoms ?
The car is a 99 2.3 f door accord

 

just some suggestions; check motor mounts for torn rubber or loose fasteners, confirm timing of balance shaft components, check accessory belts.

 

Is the oil pump and balancer shaft aligned? You can check by putting it on TDC and pulling the bolt above the axel and put a pin through it. Thats how you check the oil pump. And the balancer shaft should also have a mark on it also.

 

be sure you reinstalled the 4.5x11mm key in the keyway on the on the crankshaft, this keeps the crank pulley turning with the crank... also be sure your crank pulley bolt is tight.