390Dancer

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.

BlueSteel

Go get a new MAF sensor. My 99 F-350 did the same thing. At 2000 rpm it would stall spudder and die. I let it set and then all was well. Then it did it again shortly. I replaced the MAF and never had a prob since.

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Freshmeat

If you're going to do it, do it right- get a bigger one from BBK or Edelbrock!!

Oh- and he has a SOHC 4.6L, not a 5.0- they quit putting 5.0 in the Grand Marquis when they switched the body in 1992.

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SeaBass

My 94 Crown Vic LX just started doing that as well. It quit twice and started right back up at highway speeds. Now it has just died several times even at idle. It seems like I am losing Ignition. Fuel would die gradually or sputter. This just dies. I can start it back up almost immediately. At speed it restarts itself. I'm thinking ignition module, EEC, or the wiring to it. It's tough to pinpoint an intermitent problem. I hate to through parts at it (especially when I'm paying for them). Any suggestions? Car does not miss at all. Purrs like a kitten then just dies. Got to be Ignition right?


By the way 28 to 32mpg is unbelievable for a Grand Marquis. I get around 21mpg.

Lambykin

Normally when these "newer" cars die at highway speeds, and can restart, or can restart after cooling down, they are beginning to show signs of ignition module problems. By "newer" I'm referring to anything with an electronic ignition, and these cars have been around for more than 20 years now. This problem isn't specific to Ford, but different car manufacturers give it a different name. GM calls it an ECM, Honda calls it an "ignitor". In all scenarios, whether it's in a "black box" or not, it's essentially a special type of transistor. Mounting locations are different depending on make, model, and year. This problem usually begins intermittently, and may appear to "go away" during colder times of the year - but don't worry, you'll be boldly reminded one warm spring day. Over time, it gets worse. Eventually the component will suffer a total failure rendering the car useless (at this point it's a lot easier to diagnose, but you're now stranded at the side of the road & require a tow). Replacement of this component is usually easy to do, but don't be surprised if it's a little on the expensive side.

I replaced my Duraspark II (ignition module for the '85 Crown Vic) last fall when I suddenly began to have hard-starting problems when I shut down the engine after a trip, and tried to head off a short while later. It cost me $85 Canadian. I could have spent only $40, but I was suspicious of the quality, and the $85 dollar unit was "heavy duty". This was the cheapest module I've purchased for any car I've owned. Honda's "ignitor" is a large bare transistor that mounts to the distributor on older models, and cost around $120 many years ago. To save on costs, don't purchase this item from the dealer. Instead, go to NAPA, or wherever. In most cases you'll save yourself money.