How to soften a ‘trucky’ ride

Dear Doctor: I own a 2014 Chevrolet Impala. I’m happy with the car, except for the suspension. It’s hard, noisy and very “trucky.” It came with 235-50-18 tires. Is it worthwhile to replace the rims and tires with 215-60-17? If so, then should I also recode the speedometer? Some owners have replaced the shocks with very expensive ones with very little results.


Dear Joe: Check with the local tire shop and see if they have a 60 Series tire with the diameter of a 215-60-18 tire. As long as the overall height is within one-quarter of an inch, then a speedometer re-calibration is not needed. When selecting a replacement tire the lower the speed rating the softer the sidewall, which will result in a softer ride.

Dear Doctor: I have a 2008 Pontiac Grand Prix and when driving in heavy rain the car goes into “reduce power” (that is what comes up on the display). I then lose engine power and if I don’t pull over in time, the electrical system shuts down. After this happened the first time I took it to a dealer and they replaced the throttle sensor, crankshaft sensor, and a connector that was on a recall to have it sealed. During a recent heavy rain storm the same problem happened again. When I pulled the car over and shut off the engine for five minutes, it restarted and I had full power again. Any suggestions?


Dear Scott: It is difficult to diagnose this issue if there are no fault codes recorded. However, when I get a vehicle in my shop with this kind of issue, I get a water hose and start spraying water from the bottom up with a scan tool connected to the vehicle. This allows me to see which circuit caused the problem.

Junior Damato is an ASE-certified Master Technician. E-mail questions for publication to info@motormatters.biz Mail questions to: Motor Matters, PO Box 3305, Wilmington, DE 19804.