Metal-to-metal contact may cause vibration

Dear Jerry: A rough idle or vibration could be a slight engine misfire or metal-to-metal contact. The contact could be an engine mount, exhaust, or even a belt-driven pulley accessory. Some simple checks need to be done. First, disconnect the drive belt. Start the engine and observe if there is any difference. Next, using a large pry bar with the engine running and vibration present, pry the engine to either side and again note if the vibration changes. You may want to go to an independent shop for another opinion.

Dear Maureen: When a part is discontinued you have a few options. The first is having the local Ford dealer do a search of any dealers that may have one in stock. Next, check auto parts stores that may carry an aftermarket brand sensor. You can also check salvage yards in your area. Also, I recommend that you remove the faulty sensor and check out a sensor for a later model, or different model, Ford vehicle. Sometimes the difference can be the length of the wire while the actual sensor is the same.

Dear Matty: I see Subaru vehicles overheat as a result of cracked cylinder heads, warped cylinder heads and/or leaking head gaskets. Sometimes the blue liquid will not change color at the radiator when performing a coolant test because the hydrocarbon level is so low when the engine is not under load. The best way to check for hydrocarbon in the cooling system is with a gas analyzer.

Dear Cathy: I would like you to have the idle control motor and throttle position sensor replaced. A stalling problem condition such as yours is not spark or fuel related. I have come across many Ford vehicles with this issue whose computers did not have stored fault codes and fuel pressure was at specification. Ford computers are very tough and seldom fail.

Dear Brian: Your car has multiple computers that are in constant communication with each other. If the fault happened often, then a scan tool in the movie mode could capture all computer functions and pinpoint the area of lost communication, Unfortunately, without having the problem occur in the shop it's almost impossible to find the fault.

Junior Damato is an ASE-certified Master Technician. E-mail questions to info@motormatters.biz