Q. My GMC Terrain has been diagnosed with a random misfire. The dealer told me it is the gas I am using and they will need to do some major disassembly to solve the problem. The engine runs fine and has this occasional check engine light. What can be done, without taking the engine apart? 

A. Gas quality can be part of the issue, and it makes sense when you can to use TopTier gasoline. But I also believe at the heart of these problems is direct fuel injection systems that seem to allow more combustion chamber carbon buildup. This is due to the way fuel is injected directly into the combustion chamber, which doesn’t allow the fuel to clean the valves as it does in traditional port injection engines. In the past I have had good luck solving this issue running fuel cleaner directly into a large vacuum port. There are solvents and special adapters made just for this purpose.

Q. I have a Ford Edge 2013 with 228,000 miles on it.  It runs well and was at the time of purchase, fitted with all the latest amenities, so I’m enjoying the car for the next period of its life after my wife drove it for eleven years.  It has a disturbing hesitation that at first my mechanic thought might be gas related and recommended an additive, but this did not work, and the problem persisted.  The car checked out on the computer, and I said it felt as if it might be a transmission slip issue.  I’ve become less concerned about it and, so far, has not gotten worse with time.  It occurs while entering an on ramp that requires the car to accelerate under load and climb, but it rectifies itself in seconds.  What do you think I am experiencing with my trusty Ford Edge?  I’d like to continue to drive it.  Am I furthering damage by driving it under its present condition?  I don’t want to spend too much money given the age of the car. 

A. I would road test the car with your mechanic so they can experience exactly what you are experiencing. At 12 years old, it certainly could be a transmission issue which is not uncommon in this vehicle. The other possibility is the fuel system could be at fault. A weak fuel pump could also be a possibility. At this point you will need to go back to the repair shop for additional diagnostic testing, which should include a test of fuel pressure under load. The question, are you doing additional damage by continuing to drive the car? If it is the transmission the cost to repair it will be the same now or later, if and when the symptoms get worse. 

Q. What causes my Kia Soul to use so much oil? There are no leaks so I brought the car to the Kia Dealership and they said they could not do anything until the  motor seized up. How stupid is that!

A. The issue with many Kia/Hyundai engines is the piston rings gum up and allow oil to bypass the oil rings and be consumed during combustion. Typically, the dealer will start with an oil consumption test. They will change the oil and have you come back in 1000 miles. If the oil is still at or near the full mark, Kia considers the oil consumption normal. If the oil is low, then the dealer will try an engine cleaning. This cleaning is supposed to remove the build up at the rings. My experience is that this procedure, which is necessary for warranty works, almost never works. If after the cleaning the engine still uses oil, and the car is under warranty, the engine gets replaced. 

Q. I have a 1966 Ford Falcon convertible that my wife originally got in 1974. It is a car that does not get driven enough. I have been lucky over the years to not have massive repair bills, but I have always been concerned about being overcharged and whether the work being done is by capable mechanics/shops. Or maybe I just expect better customer service or better service overall. I prefer to have someone close since when something must be done it always needs overnight or multiple days in the shop. Again, is that normal or can the service be better?

A. This is a great car, relatively simple to repair with easily available parts. The problem as you found is that good shops are busy. Back when shops had plenty of help, classic cars were a great fill in work, especially in winter. Today with less quality shops and the challenges of finding qualified staff, almost no one has time for classic car work that can take up valuable shop/bay space. As warm weather comes around go to car shows (look for Ford owners) and ask around you may find some leads. 

Q. My 2018 Subaru Outback info screen has been beeping and changing stations on its own, sometimes the screen freezes and I cannot do anything. There is no rhyme or reason to when it happens. I have searched several YouTube videos and so far, everything I tried is temporary. Help!

A. This is an issue we see in many vehicles that have infotainment screens. Just like with a computer tablet over time the touch screen can get wonky. With your Subaru and many other vehicles, the issue is the screen itself and the fix is to replace it. The screen delaminates and causes the phantom changes. There was a class action lawsuit but as far as I know it did not go anywhere.