I have a 2000 Grand Marquis and recently (about 2 months) The car runs just find and shifts as normal but when I get up to speed 60+ and I have to let off the gas for whatever reason, I Have to slow the car down to around 25mph before i can accelerate anymore.

Any Ideas?

114k Miles

 

The problem you described is most often caused by a faulty "Throttle Position Sensor".
At 114,000 miles, your sensor would normally wear out, and should be replaced.
I purchased a brand-new Motorcraft T.P.S. at Amazon.com -- (great price, fast delivery).
Very easy to install in just a few minutes -- no special tools required.
I ordered and installed a Motorcraft "Idle Air Control Valve" at the same time.
Now at 155,000 miles -- Idle speed and transmission shifting are as smooth as silk.

 

I replaced everything listed and it did not change at all. I did however, take it back to the interstate and get it up to speed. But this time i turned overdrive off and it runs as it should no problems.

Any Ideas?
Thanks

 

Beats me, man --
Good Luck !!