1992 Mercury Grand Marquis Transmission issue?

  • Thread starter Thread starter Matt
  • Start date Start date
M

Matt

Guest
It feels like the transmission is not kicking down when it should, but shifting rapidly back and forth from one gear to the other, which feels like a miss. Wide Open Throttle shifts are not effected, cruising is not effected, but when coasting and applying a little throttle to accelerate it won't downshift and stay. I ran a scan using my Snap On MT2500 and got a DPFE code. Swapping that out tomorrow, but doubt that's the cause. Also, the Odometer and trip do not work, but the speedo does. What gives? BTW, the genius at Cottman says to use higher octane fuel. At least she didn't pay for that advice.
 
Sounds like a vacuum issue, either a collapsing vacuum line or a bad modulator. Your odometer issue is a bad speedometer head.
 
Back
Top