sr20 vibration when idle

[MaKaVe1i]

when im at a stop r when my engine is idle, it starts to rumple or shake. but if i put my brake in, it stops or if i turn on my defroster, the one button under the e-llights. My car is a nissan 240sx 89' wit a redtop s13 sr20det. Any reason or fix i kan do?

[NISTECH]

check for something attached to the engine rubbing against the firewall or against your crossmember or unibody. also check your motor mounts see if they have collapsed being it goes away with slight idle changes from loads i think something on the engine is rubbing against the body somewhere.