I own a 2009 Volkswagen Passat 2.0 four-cylinder. The engine light is on and the engine runs rough. The fault codes are p12a2 and p0171. I have had the car to three shops and no one knows what the problem is. Do you have a suggestion?
Dear Bill: Lean conditions can be caused by multiple problems, especially in imported engines from Volkswagen and BMW. The first step we do on most check engine light problems is to check the codes and identify when the problem happened in freeze-frame memory. The next step is to visit our Identifix site to look up the codes, and review what other master technicians have seen. With the correct information and trouble flow path of checking, this reveals a simple repair, which in this case could be a faulty crank case pressure-regulating valve.
Dear Doctor: Please settle an argument I’m having with my brother: When I pull up to a traffic light that I know will be red for an extended period, I shift the car into Park to avoid the strain on the brakes trying to hold the car back from its normal tendency to move forward. I say this saves wear and tear on them. My brother argues that this strains the transmission and will lead to transmission problems down the road. What are your thoughts on this?
Dear Bill: Today’s vehicles are unlike the vehicles of years ago. Let’s say that you are at a long train-crossing gate, under this condition placing the shift selector into Park would be a good idea. The brakes will not have any wearing effect when you are stopped and waiting to move. As for wear on the transmission, there is no extra wear.
Dear Doctor: I recently purchased a used 2005 Ford Explorer and brought it in for an oil change and inspection. The technician suggests I replace the spark plugs, as well as the spark plug wires. The estimate was just under $500 for parts and labor. I’ve never paid so much for this service. Is this the correct price?
Dear Mary: In some engines, especially a V-6, the intake manifold must be removed to access the spark plugs. This then requires a new set of upper intake runner gaskets. Another concern on some Ford engines is breaking the spark plug when trying to remove it from the cylinder head. So yes, the spark plug and wire replacement can be expensive.
Dear Doctor: I own a 2011 BMW X3 four-cylinder with 44,000 miles that has an intermittent engine skip. I replaced the spark plugs and the problem is now worse. Your advice would be appreciated.
Dear Mark: A common problem over the years is faulty ignition coils. Our Identifix site shows technical service bulletin SIB121814 instructs mechanics not to use the Bosch coil, but to use a Delphi coil instead. We have performed this service in the past to solve the problem. Just remember, you need to replace all four.