help..rumbling noise!
 

so I just fished replacing my motor mounts today. The old ones looked liked they were sliced open with a knife. Anyway, I tightened everything to specs and took her for a test spin. There is absolutely no vibration anymore which is great but now whenever I accelerate really quickly in 1st, 2nd, and 3rd gear there is a rumbling noise that I can hear and feel coming from underneath my feet. It does not happen in 4th or 5th. It only happenes when i quickly accelerate. If I give it a smooth acceleration there is no noise. Also, there is no hesitation or stutter while this happens, the car runs smooth.

I recently replaced the wheel bearings so I know its definately not them. The noise sounds like a bag of rocks rolling around on the ground.

In the past 2 weeks there have been 2 instances when the car would start and then almost die. I don't know if this has anything to do with the problem. I have only heard this sound since I replaced the motor mounts today. What could I have done wrong?

mounts
 

if the mout 8mm bolts are too long and touch the rubber mount part this will happen..very common to change length or have to shorten the bolts on conversion mounts

yeah. i noticed that on the drivers side the bolts I bought did not exit out of the back of the mount, but the ones on the passenger side were protruding about 1/8th to 3/16 th of an inch or so. I ordered the shorter bolts but I guess they were'nt short enough. I 'll have to go to the hardware store and try to get shorter ones and see if the problem goes away.