Q Two years ago, I bought a new set of Yokohama tires for my 2006 Kia Sedona van. After having the tires rotated and rebalanced last year, the vehicle developed a slight pull to the left. I took it in again and the shop rotated and balanced the tires again and tried an alignment. Now, the pull is a slightly more than it was. They rechecked the balance job and the alignment was all within their specs. I would like to see this fixed. Can you help?
ASince the tires and wheels have been balanced and rotated several times, they are not likely the source of the pull. Ask the shop to check the alignment of the upper spring seat plates. These components locate the top of the spring/McPherson strut assembly in the unitbody shock towers. According to my Alldata automotive database, Kia issued service bulletin KT2006040701 dated April 2006 addressing the problem. The bulletin describes the procedure of checking and, if necessary, realigning the spring seat plates in small increments to eliminate a slight pull or drift while driving.
QI have a '91 Toyota MR2. It runs well enough, but occasionally when I come to a stop the motor revs up and down repeatedly. When I tap the gas pedal this will stop, and it may or may not happen again the next time I come to a stop. If I turn the air conditioning on, it doesn't happen at all. I would appreciate your input.
ATry adding a fuel system/combustion chamber cleaner such as SeaFoam to the fuel tank. Better yet, introduce the cleaner directly into the induction system via a vacuum port. The idea is to de-carbonize the intake and combustion chambers. This service is also offered as a professional induction cleaning.
With the age and mileage of your vehicle, it's possible a buildup of carbon deposits is absorbing a percentage of fuel sprayed from the injectors, creating a slightly lean fuel/air mixture at idle and the idle speed fluctuation you've described. Turning on the A/C causes the engine management system to increase the idle speed slightly, masking this minor issue.
Several other possibilities: Try a fresh oxygen sensor; the original may be a bit old, slow and not quite fast enough to keep fuel/air mixtures optimized at idle. And check and clean the throttle body, idle control system and EGR valve.
QI have a 2003 GMC Yukon that has had a noisy 5.3-liter engine since new. The dealer claims it's piston slap, even though the engine was at full operating temperature. I claim it's due to oil draining down from the lifters. One thing they recommended was an engine oil flush for $400 with no guarantee that would do any thing at all. It now has 110,000 miles and is getting noisier. I am worried about how long the engine will last. I would like to keep it to 300,000 miles or more.
AAn engine flush would not address piston slap and it seems unlikely lifter drain-back and clatter would have been there since new. But there is one similar 'ticking' noise that could be caused by a failed O-ring between the oil pump and oil pump pickup screen. According to GM bulletin 02-06-01-038 dated December 2002, this problem allows slight aeration of the oil, which can generate the ticking noise for the first few moments after startup hot or cold and likely would have been noticed during the first few hundred miles of operation.
I don't know if you'll have any luck under warranty, but it's not a huge job to pull the oil pan to check and replace this O-ring.