Antelope Valley Press

Is this fuel-saving device way too good to be true?


Dear Car Talk: I’ve been reading about a device called Fuel Save Pro that plugs into my car’s OBD II port under the dashboard. It says I can save 15% to 35% on fuel costs by letting this device optimize my car’s fuel settings dynamicall­y while driving. The cost of the device is under $100, so that sounds like a good deal — unless it’s not.

What do you think? What does the device really do? I called my car dealer and talked to the service department, and they had never heard of it. — Don

Neither have I.

The manufactur­ers optimize your engine for the best balance of performanc­e, fuel economy and emissions. And they spend millions of dollars a year trying to squeeze a percent or two more fuel economy out of their vehicles. So, if there were a way to increase fuel economy by 15% to 35% for $99, trust me, it would already come with your car.

I’ve never heard of this particular device, but most of them do two things. First, they remap the engine and transmissi­on parameters that the auto makers have gone through great trouble to set. And if they boost one variable, like fuel economy, it will undoubtedl­y come at the expense of one or more of the others. So, the downside is that you might damage your engine or transmissi­on, void your warranty, ruin your catalytic converter and/or fail your next emissions test.

The second thing they probably do is exaggerate the results. So, you might not get anywhere near what they promise — even with all that downside.

Generally speaking, Don, when something sounds too good to be true, it is.

My advice would be to forget about this thing, drive gently, avoid jackrabbit starts, quit warming up your car, and make better use of that $99 by applying it to your gas bill.

Dear Car Talk: I have a 2014 Toyota Tacoma. I cleaned the mass airflow (MAF) sensor with electronic­s cleaner and now the truck is running terribly.

A friend of mine said I probably ruined the MAF sensor because I didn’t use MAF sensor cleaner. So, I replaced the MAF sensor with one from AutoZone, hoping for a quick fix.

It’s still running terribly. I disconnect­ed the hot wire for about 15 minutes, then reconnecte­d it, but no improvemen­t. I’m not sure what to do next. Can you help me? — Jeff

I’m going to guess that the MAF sensor is not your problem, Jeff. I think you must have done something else by accident when you went in to clean the MAF sensor.

The mass airflow sensor measures the mass of the air coming into the engine. When air is drawn in, it passes the MAF sensor, which tells the computer how dense the air is, and the computer adjusts the fuel-air ratio accordingl­y.

Now you’ve got a brand-new MAF sensor, which is pretty hard to install incorrectl­y — you just plug it in. So I’m going to guess that the new MAF sensor is working. Since my only hint is that you sprayed — I’m guessing here — a proverbial boatload of electronic­s cleaner into the air intake in an attempt to clean the original MAF sensor, one possibilit­y is that you managed to foul one or more of your spark plugs with that stuff.

If you fouled a plug or two, the truck would run terribly, even with the MAF sensor working. That’s because you’d be running on, say, four cylinders instead of six, which would cause the engine to shake and sound like it’s stalling.

An easy way to test if the truck is running on all cylinders is to disable one cylinder at a time — while the engine is running. So, if you unplug the coil for cylinder number one, for instance, and the engine keeps running exactly the same, that’s a pretty good hint that cylinder one was not firing to begin with.

Do that for each cylinder and you’ll find out which ones aren’t working. Then you can figure out why. You could have bad plugs, bad coils, or you could need a valve job. But start by checking for fouled plugs. Hopefully you’ll find a few and it’ll be an easy fix. Good luck.

Got a question about cars? Write to Ray in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at

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