I've swapped out my TPI 305 for a 350, changed to 350 prom, injectors and knock sensor. (1987 GTA 350 TPI auto)
I changed the intake last summer as well to HSR.
The problem I have is a rumble when I accelerate and I just cant figure out whats the cause. This was a minor problem after installing the 350 but worse now.
Feels like Im loosing power when throttled.
Engine/ trans mounts are solid, driveshaft is good, could a bad harmonic balancer cause this problem?
Im just tired of this rumble and its only getting worse and Ive run out of ideas to the cause.
Any advise would be appreciated.

 

I got the car in the air noticed most the vibration coming from the transmission and engine.
At 2000 rpm the car shakes and rumbles, runs ok at 1500rpm and higer than 2600rpm, could this be my flexplate or anything else come to mind?

 

probably needs a programming but without seeing the actual symptoms its hard to tell.Keep trying to describe it better though

 

Fixed vibration problem, ends up being the transmission loosend from all the engine vibrations over the past year, just needed to be tightend.