Can't Diagnose Problem On Car
 

Okay I have a 98 Gt mustang. If I go wot in FIRST gear i feel a horrible bumping in the drivers side floorboard. Passengers don't feel it. I shift into second and it stops and feels normal. What could this be? Auto tranny, stock rear end. Mods are exhaust/intake/drilled Seperator plate and valve body in tranny/and it used to be tuned. My dad says it could be a motor mount needing to be replaced and it only bumps through first gear because of the low end torque. What do you think?

I think you signed up at the wrong forum :nod:

Sounds like a trans mount, not a motor mount.

i agree, check trans and motor mounts. i know with my car (not a mustang) after the exhaust install it would hit the floor when you get on it in first gear. the cure for me was poly mounts. you may have a broken mount causing this issue.

Okay thanks y'all. I'm trying to get this car fixed so I can sell it and buy an ls1. Ls1 has ported heads, cam, dyno tune, full bolt ons and 3:73s

Car sold. Ls1 comin soOn