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Fuel Pump Assembly? With Module?

I inherited a 1999 Mercury Mystique (67k miles) from my grandmother who drove it about 4 miles a day for the past 10 years. She never had a problem with it, but probably neglected regular tune-ups and oil changes.



We drove the car 80 mi towards our home and stopped for some errands. A few different stores, all pretty close but with different parking lots, no problems.



We then get in the car to continue the next 50 mi home, and it doesn’t start. Battery is fine, it’s turning over, but not catching enough to start idling. Got it towed for visit #1 to the mechanic.



After 2 weeks with it, he can’t replicate the issue. He gives it a thorough tune-up (which he said hadn’t happened in awhile), new spark plugs, 2 new tires, and says it’s good to go.



We then drive 50 mi to the DMV to complete the title/registration in New York State. Stopped for lunch on the way up, restarted afterwards, got to the DMV with no issue. Then we needed to get something notarized, so drove the car to a few local places; restarted fine each time… except the last.



Mechanic from across the street walks over and says I need a new fuel pump. I called mechanic #1, who agreed. After an hour of leaving the car alone, she started like a champ, and we drove back to mechanic #1.



We replicated the issue in his parking lot that afternoon: turned off the car and tried turning it on again (while still warm), and it wouldn’t start. He sprayed starter fluid under the Air Filter Cover (?), and that allowed the engine to rev until the fumes went away. So he felt confident in the fuel pump replacement.



Now he’s had the car for a week and can’t replicate the issue again! He wants to do the fuel pump assembly with the module, but thinks it could also be electrical problems with the relay.



Do you think I need just a fuel pump ($200 + labor), fuel pump with new module ($400 + labor), or more?



We’re deciding if we want to put any money at all into it, as we’re worried about uncovering more and more issues. The mechanic said things generally look good inside, and when it runs it drives great.



Any advice, Click and Clack (and friends)?

Four miles per day for ten years is the toughest life a vehicle, any vehicle, will ever know. The engine and drive train in this car haven’t been fully warmed up in ten years. Until, that is, you drove it 80 miles, then another 50, etc. This doesn’t even take into account the neglected maintenance.

This is a perfect example of why a low-mileage used car is not necessarily a bargain.

If you intend to put this car into general use on a day-to-day basis there’s no telling how many problems might start cropping up. You may be lucky and there won’t be many, or you may find a new problem every month. No one can say for sure.

Be that as it may, the fuel pressure should be tested before assuming the fuel pump is faulty. Has anyone replaced the fuel filter? A clogged filter could cause the symptoms you describe.

These cars were never paragons of reliability. If it’s running I’d try to sell it. Take whatever you can get and let it go before it becomes a money pit.

Thanks so much for your fast reply!

He took down and replaced the fuel filter (which is inside the tank?), and said it surprisingly didn’t look bad. He called today and said after letting it idle for an hour, then drove it around the block, the issue replicated. At that time he got a fuel pressure reading-- super low.

We can’t dump the car for at least 2-3 months (how long DMV says it will take to send the new title), so we’re thinking do this one repair, use it for a few months, and see how it goes.

In your opinion, would just a new fuel pump work (after-market, Napa type), or should I get a new assembly with module directly from Ford? With labor, the difference is about $300…