, Salem, MA

December 28, 2013

Auto Scanner: Gas gauge malfunctioning in ’06 Trailblazer

Auto Scanner
Larry Rubenstein

---- — Q: I have a 2006 Chevy Trailblazer LT 4WD. It has about 50,000 miles on it. It is no longer under warranty. I have recently begun having problems with the gas gauge (and also the digital display of mileage left before gas is needed). Both read empty (0 miles left — low fuel) when the tank has just been filled. In fact, the gauge reads empty for several miles after fill-up. Then, it will sporadically jump around between empty and full while I am driving around. It goes up and down all day long. It’s enough to make you crazy. So, I have no way of knowing when I actually need gas except to set the trip meter and fill up when I reach 200 miles. So, that is what I have been doing. Any idea what is causing this?

A: Most of your major repair facilities have scanners that link to your car’s computer. With this scanner, they will be able to monitor the signal from your fuel tank and also be able to emulate a signal to your instrument panel. This is how the problem is isolated. Expect to spend between one to one and a half hours for diagnostic costs to be able to nail down the problem. The cost of the repair itself, of course, is dependent on which component has the problem.

Q: I recently purchased a brand new 2009 Toyota Tacoma 4X4 with the 4.0 L V 6 (1GR-FE) engine this past September. Due to health issues, I have driven the vehicle only 275 miles in four months. My question is should the oil and filter be changed at this time? Any tips or suggestions concerning this vehicle would appreciated. Could you please explain what (1GR-FE) stands for?

A: If you use the car at all, you should minimally change the oil twice a year. My recommendation for the average driver who puts on between 10,000 to 12,000 miles is an oil change every 3,000 miles. Not only does it refresh the oil in your system for a cooler running engine, but it gives the technicians a chance to see any problems in its infancy. 1GR-FE is the designated code for your particular engine.

Q: I have a 1996 Saturn with (the odometer says) 67,000 miles on it (which we do not believe, but anyway...) Here is what is happening: The car will suddenly accelerate at certain times. For instance, while idling at a traffic light with the brake 75 percent of the way down, it will suddenly accelerate. If the brake is 100 percent (to the floor), you can see the arrow (rpm) move vigorously, but the car does not accelerate. If I am at a drive-thru, I make sure I put it in park to prevent acceleration (if I think quickly, I can prevent the acceleration right before it occurs, for instance as I am slowing down in traffic) Needless to say, I have taken it off the road until I figure it out. It was a perfect little car for my daughter to go back and forth to high school, and I would like your opinion on what you think you could be wrong and if it is worth trying to eke out another year or two.

A: Sounds to me like you have an idle air control motor that’s lost its marbles. This is not a hard problem to diagnose. Here’s the deal. If your idle is jumping up and down, the technician has to monitor the IAC to see if it’s acting on its own or being commanded to step the idle up. Least expensive repair would be if it’s acting on its own, and a replacement with a cleaning is all that’s needed.

Car Care Tip: What’s the difference between an engine and a motor? Motors are driven by electricity; engines are internal combustion. From my family to yours, Happy New Year, with a healthy 2014.


Larry Rubenstein is a master technician who owns a North Shore service station. His column appears every Saturday. Write to Larry at The Salem News, c/o Auto Scanner, 32 Dunham Road, Beverly, MA 01915, or send an email to