Q: My 2018 Subaru Impreza's owner's manual specifies 0W-20, full synthetic oil. Our 2010 and 2011 four-cylinder Toyota Camry owner's manuals specify 0W-20 oil, but they do not specify synthetic oil. I have been replacing the oil in these Camrys, faithfully, every 5,000 miles or six months as the owner's manual recommends. So is there any reason not to use non-synthetic oil to save some money? The Camry owner's manuals do specify the oil grade must be ILSAC multigrade engine oil. Is non-synthetic oil ILSAC grade?

A: ILSAC, the International Lubricants Standardization and Approval Committee, was formed in 1992 by the U.S. and Japanese automobile manufacturers associations to define the need, parameters, licensing and administration of lubricant specifications. Since ILSAC's inception, all motor oils, synthetic or conventional, bear the ILSAC grades. Zero (0-xx) oil can be made only from synthetics. But other grades such as 5W-30 may or may not be synthetics.

Jeep has the shakes

Q: I have a 2014 Jeep Grand Cherokee with 77,000 miles on it. Periodically the whole front end and the steering wheel shake very badly. I have to slow down, and then it goes away. I can drive it for two or three weeks without it doing it again. I took it to the Jeep dealer, they kept it for two days, checked everything on the front end and periodically drove it, and they could never get it to happen. Any ideas?

A: I'd start by replacing the steering damper. It looks like a large shock absorber attached to the front of the steering linkage. But don't overlook other worn parts like ball joints, tie rods and especially the track bar attachments. The damper may help, but in the long run the wobble will return if any steering or suspension parts are worn.

Mystery pedal

Q: When I purchased my 2013 Chevy Malibu, a dead man's pedal was listed on the invoice. What is that? And if it's important enough to be listed on the invoice, shouldn't every vehicle have one?

A: I haven't heard of a dead man's pedal. However, many vehicles have a pedal on the left side of the footwell upon which you can either rest your foot or brace your foot during spirited driving. The pedal has no other purpose, so I guess you could call it dead. Or, in the words of Monty Python, "It isn't dead, it's only resting."

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician. His writing has appeared in automotive trade publications, Consumer Guide and Consumers Digest. Send automotive questions along with name and town to motormouth.tribune@gmail.com.