My friend has a 1997 Mercury Marquis
5.0 I think. Great car only had 80,000. After about ten thousand miles when driving at highway speeds, say 70 to 80, the car would die, kinda like it had a governor, but kept slowing till about 40, (no power,like outta gas) or he would have to pull over, either wait, restart & it would be ok. Some times if he has a long drive & it sits over night, after acting up all day, the next few days or weeks it's fine, then again.....problem worsened, we replaced the TPS. This seemed to fix, couple of weeks later same thing. We replaced the TPS again
with same results. After having code checked at Auto Zone, coes read "needs o2 sens left and right bank lean" & check TPS. The other thing is it has a date & message written on the fan cover "Reprogramed 10-21-2003?
We have heard a lot of stories, 1. you need the "Ford TPS", 2. The TPS may cause the bad o2 reading~!
I just can't understand the infrequency of the problem, oh by the way "no Check Engine Light", thats correct, the light is not on & great gas mileage 28 to 32 depending on driving~! It did have a problem at first, but we returned it to the used car dealer & less than 30 mins he said all set. Could he have killed the light? The dealer has been nice before and after, new tires, E-Brake cables, Battery, brakes, gas filter. My friend is not rich but not poor, but doesnt want to pay and pay and pay till they fifure out what's wrong. Should we just take it to Ford? Is it the brain that needs reprograming? Any ideas are gladly accepted.......We live in Massachusetts just in case you need to know.