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Nervous Taurus: hesitating and shutting off after a long drive (perhaps related?)

I have a 2003 Ford Taurus with 147,000+ miles. My nervous Taurus has been hesitating when I pick up speed, is slow to pick up speed, and shakes a bit when up to the speed it needs to be. One of my mechanics that drove it suggested it may need a tuneup, which sounds about right. However, there is an additional problem that is a bit odd.

I have a one hour commute (one way) twice a week to one of the schools I teach at. Every once in a while at the tail end of my trip, the car hesitates a lot, the battery light comes on, and it slowly winds down to where it cranks, but won’t start. However, if I let it rest for a half an hour or so, it starts up fine and I go along my merry way. I’ve taken it to the mechanic twice after this problem and they thought it might be an alternator, but when they ran a test on it, it was putting out adequate voltage (not sure if that is the correct terminology) and it didn’t appear to be needing replacement, so they’ve been stumped. I do notice this happens more often if I don’t drive the car for a few days or a week.

With all that, my question is does this sound like it needs a tuneup and would the second problem of shutting down be related to the tuneup? The mechanics don’t seem to think the second problem would be solved by a tuneup and have suggested a new alternator despite the volt meter reading find (with the caveat that it might not fix the problem). Any help would be greatly appreciated.

Another important detail, I had a tuneup about five years ago (perhaps 30,000-50,000 miles ago). Not sure if that is the typical amount of time you need a tuneup or not.

Get a 12 volt meter to stick into your aux power plug and see what the volts are doing during your trips.

It’s not known what is missing when the engine refuses to run (spark or fuel) so the number of possibilities goes way up.

The most likely would be a crank sensor or fuel pump although those only scrape the surface.

Yes, a ffalky alternator going in and out could also cause this but I’d want that verified before spending the money to replace something that may not cure the problem. I tend to think the problem is not the alternator and the battery light is coming on because the engine is about to die.

I think I would want a more definite assurance that it is the alternator before you invest in a new one. It’s very possible that the alternator light comes on because the engine is hesitating and not turning the alternator as fast as it should.

I agree with “insightful” and get a $10 volt meter (Amazon) that simply plugs into the cigarette lighter. You can monitor the voltage while driving and see how and when it starts to fluctuate and what the voltage actually is.

You might have other problems, such as fuel pump, fuel filter, damaged vacuum hose, etc.

Thanks for the feedback so far. I’ll definitely purchase a volt reader and monitor the voltage that way. I didn’t know one of those existed where you could plug it into your cig lighter, so that is awesome to find out. Getting a new alternator is a bit of an expensive experiment to conduct. Also, I did replace my alternator in 2008, so not sure if nine years is a typical time frame for them to go out.

As far as the other suggestions go, I did replace the fuel pump this year. I have also replaced the steering pump and water pump this year in case those could be related in any way. 2017 has been a litany of issues.

30-50K miles between tune-up is a pretty long time. I would ensure that the basics are covered, air filter, spark plugs and plug wires and fluids changed. You could be surprised how well a clean air filter improves performance. At a minimum it keeps your car healthy and, hopefully, at a decent gas mileage. That should be done regardless of your hesitation problem. Start with that and see what happens.

Yeah, that is what I was leaning towards doing since it has been a while since my last tuneup. I’m going to try that and see what happens. Like you said, it needs it done anyhow.

This engine has nothing to “tune” to require a tune-up. It should have platinum spark plugs, the maintenance schedule calls for replacement every 60,000 miles. If there is a misfire there could be a failed spark plug, proper diagnoses is needed before parts should be replaced.

Suggest to focus on the second problem, the battery light coming on, as that might be causing the first symptom also. The battery light should only come on when the key is in on and the engine is not running, and go out once the engine starts. It should never come on when the engine is running. So that’s a big clue there’s something major wrong with the car’s basic electrical system.

Could be a slipping alternator belt, defective battery, faulty voltage regulator, corroded wires between alternator and battery, or just an intermittent alternator. Monitoring the voltage at the battery is a good idea, it should be around 12.6 volts in the morning before you start the engine. Immediately after starting the engine it jump into the 13.5-15.5 volt range, and stay in that range while driving. Newer vehicles sometimes involve the engine computer in the alternator voltage regulator function, so if that is the case with your Taurus design, that’s another possibility.

If I had this problem myself I’d start with a basic charging system and battery test. Most any inde shop will do that for a small fee. Concur w/advice above, a “tune-up” is not the place to start. If your car is behind on the routine maintenance schedule, it always makes sense to bring all that up to date of course. You don’t want to be spending money diagnosing a problem that is due to deferred maintenance. Spend it on the maintenance instead.