bad mounts?

[one_fast_prix]

this is on my 3.1 auto cavy:

well, got the z almost back to running right, except while having the throttle slightly open it bucks/lunges. it seems to be the only time it does it. and if i hold it there it will do it until i press harder on the gas. the other thing i notice is when braking the rmps jump around slightly, but at idle and while driving they are perfect.

 

everything with the fuel system is new. no vac leaks. so i'm thinking something electrical or bad mounts maybe?

[Stevo]

Cavalier? Hmmm J-body not W-body.

 

Could be the belt tensioner.