I have a LS6 in a Porsche 944 but I have been experiencing a vibration between 2000 and 3000 rpm, after 3000 rpm there is no sigh of the vibration. I have changed plugs, coils and wires, the motor also has a set of fresh 243 heads.
Initially, I thought I had a balancing problem but I think the vibration is a misfire, its more pronounced when decelerating and the vibration is in sync with a muffled sound from the exhaust. I have been doing some logging and have found positive fuel trims and misfires around that rpm range so I ran a CALC VET and the vibration significantly reduced. The vibration is still there so I am trying to determine if I am missing something in my tune, I have attached some log files with my current tune, looking for any advice.
Specs,
- LS6 Motor
- 226, 229 - 575,585 116 LSA Cam
- 30lb SVO Injectors
- Professional Products 85mm TB