I have a problem here. I have no idea what it is. Over like 65 mph if i let off the gas i get and shaking. Its not the tranny or anything. It has to be the motor because it also happens if i slowly bring the rpms up in neutral and once they get to around 3k i get the same shaking. It doesnt happen below like 60 or below 3k in neutral. ANy ideas?

 

well its either a motor mount or the engine isnt running right

 

I was thinking motor mounts. I had new ones put in when he did the motor so maybe they have to be retightened.

 

It could be a whole number of things....

I take it this is a fresh build? timing? i see your running 24# injectors and making - 290/320... do you have a BAP???

Can you post a vid of it? maybe you are having really bad detonation from the 87/89 octane...?

Like i said, it could be many things....

 

well eliminate the motor mounts its not that. the build is almost a year old the timing wasnt touched when it was tuned. I always run mid grade fuel which i believe is either 89 or 91 and whats a BAP?

 

boost a pump.

Increases the pumps voltage and in turn increases the amount of fuel the pump can pump.

 

Your drive shaft could be unbalanced. Has it been off recently?

 

I thought of that but like i said it happens just sitting there if i bring the rpms up to 3k. And as for the bap are you saying i need one? Or if i had one that could be the problem?

 

Anyone else wanna take a crack at it?

 

when does the stock fuel pump max out? However if this is happening around 3k i dont think you have a fuel shortage. Does it continue to happen above this rpm as well? maybe something with your harmonic balancer?