Cars

What’s causing my car’s engine to vibrate at slow speeds?

John Paul, AAA Northeast's Car Doctor, answers a question from a reader dealing with a vibration issue.

Kia

Q. I have a 2015 Kia Optima with 66,000 miles that has had all its recommended maintenance done by a dealership. At slower speeds in city driving, I experience a noticeable engine vibration that is sustained whenever the tachometer remains close to 1,100 RPM. It feels like the engine is lugging, if that’s the correct term. It relents only if I let up on the gas or depress the pedal further to accelerate past the vibrating. In other words, I can’t maintain a steady speed at 1,100 RPM without the shake. What do you think could be causing this? 

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A. I would go back to the dealer and have them check for transmission codes. What you are describing sounds like the transmission torque convertor is staying locked up. This is sometimes called chuggle. Kia did come out with an update to a part called a damper clutch solenoid which may cure the issue. In addition, this could also be a combination of the transmission design and the beginning of a very slight engine misfire. At 66,000 miles if one of the spark plugs is getting a bit worn, this could exaggerate the condition. 

Q. Several weeks ago, my 17-year-old son purchased a car for $4,500. The car, a BMW, actually seemed to be a good deal, but he then returned to the same seller in the hope of getting a different color. The second car turned out to have a fraudulent title as well as an odometer that had been turned back. We discovered this through a Carfax report. I was informed by both my son and his mother that they attempted to get some of their money back and return the car, but the seller refused and may have blocked their phone numbers. Do you have any suggestions as to how we might proceed?

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A. The first thing that needs to be determined is if the seller was a legitimate car dealer or someone who just buys and sells cars without a license. The seller may be someone who just jumps titles – selling a car they purchased without re-titling it in their name. Depending on where you live, state agencies rarely get involved in private party sales. If they are a legitimate car dealer you may be able to get some help through a dealer organization or the attorney general in your state. Odometer and title fraud are subject to both state and federal laws and can carry serious fines. At this point you may need to contact an attorney that specializes in automobile fraud. 

Q. I have a 2006 Ford Mustang convertible in great condition. It makes a clunking noise which can’t be located. I have had the car checked over, but all the parts seem to be in good shape. 

A. I would take one more look at all of the suspension components including the front struts and strut bearings. At 16 years old there could also be some wear in the steering column. Your Mustang, like many cars, uses two flexible joints that connect the steering column to the rack and pinion steer gear. If one of these joints is worn, there will be a clunk. 

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Q. I have a 2008 Toyota Prius with 155,000 miles. It is in good condition for its age, but it will need a catalytic converter. The car drives fine, it is just noisy.  Any idea how much I should ask for the car and where I should list it for sale? 

A. I would list the car in cargurus.com, iseecars.com, and even Facebook marketplace. Determining the price is a little tricky. The going price for this model is $7,000 to $9,000, depending on condition. I’m sure you have a price on a new exhaust and catalytic converter, which can cost up to $2,500 depending on where you take the car for service.  I would scan the ads on the sites I mentioned and try to find a match to your car then price it accordingly. My guess is around $6,500 is about right but, used car prices are still crazy. What makes this car a bit less desirable is that potential hybrid buyers are going to be concerned about the hybrid battery life. Although buyers may be willing to take a chance on a car that gets 50 miles per gallon. 

John Paul is AAA Northeast’s Car Doctor. He has over 40 years of experience in the automotive business and is an ASE-certified master technician. E-mail your car question to [email protected]. Listen to the Car Doctor podcast at johnfpaul.podbean.com.

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