Is my tranny failing? I just had amisfire issue that caused the same vibration, but that was fixed (check engine light and all) when I spliced the EV 1 injector connectors to my 24# injectors. they fit better and were not loose anymore.

I was thinking that maybe the fuel pump is starving the engine? But my Fuel Pressure is 43 primed, 49 idle. So the pump works.

I also run a gutted cat with before and after cat O2 sensors. I put a fastman on too, so would the increase in air going into the engine, coupled with the After cat O2 sensor reading RICH make me starved for fuel at HWY speeds. My spark plugs certainly tell me i am running lean at WOT, but righ at idle. THe thing that makes me say no is that it doesn't happen at WOT. And the vibrations are not consistent, THey will vibrate then smooth out.

Or maybe i need new shocks. But i doubt its that.

Dan

P.S. If i disconnect the after cat O2 sensor, will that make the PCM increase fuel to the engine by default?

PPS:TPs, MAP, IAC, Injectors,all brand new. 145K on the car, has not had the Fuel pump changed.

 

Wait, i forgot that my father in law (a mechanic) said my front/rear shocks needed o be replaced. The vibration seems to go up and down. Could that be the problem?

I also had my wheels aligned. Do you think they could be out of balance too?

 

id say suspension problem. Either new shocks, or your tires have worn unevenly. Does your steering wheel shake at that speed?