Dear Doctor: I have a well maintained 2003 Nissan Maxima with just 37,000 miles. The "service engine" light came on. The mechanic said it needed a new throttle body, and he installed a new one. After he did this, I drove the car two miles and the "service engine" light came back on and now it has a high idle. In park it idles 1,000 to 1,100 rpm. In drive, stopped at a light, it idles at 900 rpm. The mechanic scanned it and came up with code P0507-A. He can't seem to clear it and get the idle down to normal, which is 700 to 750 rpm. What can be done to fix this?

Dear Frank: Caution needs to be taken when working on the electronic throttle body. There are very specific procedures that need to followed exactly, especially on Nissan products. In fact, on some engines a new throttle body needs to be programmed with a factory, or equivalent, scan tool. The technician cannot even clean the carbon out of the throttle body in some cases without setting a "check engine" light. The mechanic needs to contact Identifix for the correct troubleshooting procedure, as well as check Alldata for any other important information relating to the problem.

 

Dear Doctor: My 1997 Mercury Grand Marquis has only 32,000 miles on it. When I first start the car I hear a popping sound one time and then the car will start. I think one of the fuel injectors has a small leak and there is fuel in the cylinders. Is this harmful to the engine? There are no codes displayed. If it is an injector problem, then should I replace all of them?

Dear Joe: Most engine computers from 1997 and newer have the ability to record a faulty fuel injector and set a fault code if the fuel injector has an internal leak. If the injector has a small external gas leak, then in most cases this will not be picked up by the computer. If there is an external fuel leak, then you must have it repaired immediately.

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Dear Doctor: I traded in my 2012 Honda CR-V for the 2015 CR-V with that new transmission. What a mistake! At around 2,000 rpm the vehicle starts to vibrate. And at a light when sitting it starts to shake. I called American Honda and was told that's the nature of the transmission. If I knew this was the problem I would never bought this car. What should I do?

Dear Ray: In a new vehicle, especially your new CR-V, there are major changes in both fuel management, and yes, the CVT transmission. These CVT transmissions are here to stay and they do take some time to get used to. I did drive the new CR-V, and unlike your impression, I did not feel the symptoms you are complaining about. I suggest you go to the dealer and test drive another 2015 CR-V for comparison purposes to make sure there are no problems with your new vehicle.

 

Dear Doctor: My Aunt has a 2007 Honda Accord V-6 and she has replaced five batteries to date. The car has very low miles and she drive it to and from doctor's appointments. I would like your input as she is seriously thinking of purchasing a new car, and it will not be a Honda.

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Dear Victor: Some Honda vehicles have a very small battery (group size 51) that has less than 400 cranking amps. Whenever we replace a Honda battery and it has a small group series, we suggest to the owner to upgrade. With these larger group sizes, I also suggest stepping up to a high-cranking amp, such as 800 or larger. All vehicles have some parasitic battery drain. On vehicles that are not driven daily, the larger, more powerful battery should be the perfect fit -- as long as there are no other electrical problems drawing the battery voltage down.

 

Dear Doctor: I'm moving to Florida and I need help deciding which car to keep. I have a 2000 Honda Accord four-cylinder with 160,000 miles. My other car is a 2007 BMW 328i coupe with the sport package and this has 55,000 miles. The BMW has been dealer serviced twice a year since new and the Honda has also been well maintained. Which car would be the better one to keep for reliability? I don't want to deal with future reliability issues.

Dear Evan: These are very different cars. The Honda is seven years older and has many more miles. The Honda is a simple car and not as much fun to drive as the BMW. The BMW cars do well in the warm weather. While the BMW is more fun to drive it will cost you more than the Honda for routine service and if there is a major service needed in the BMW it may be expensive. The choice is yours, but I like the idea of the BMW for Florida.