Q: I have a 2004 four-cylinder Saturn VUE with 65,000 miles. It feels like the car will tear apart when I hit a large bump. Is this normal or do I have other problems?
A: The most obvious suspects are the shock absorber/struts. Whether a separate shock absorber or built into a MacPherson strut assembly, these hydraulic devices are designed to dampen, absorb and control up/down movements of the suspension. They control load/weight transfer through the chassis and soften the impact of sudden bumps on passengers. If you are beginning to anticipate and brace for the impact of bumps, the shocks are significantly worn or there are loose suspension components.
How can you test for worn shocks? Well, in the "good ol' days," you could jump on the bumper at each corner of the vehicle and count how many times it moved up and down. Unfortunately, that's not a particularly valid test with modern vehicles.
Today, a close visual inspection for leaking hydraulic fluid from a shock absorber or strut is the first test. A light "haze" of dampness on the shock itself is not confirmation of failure, but fluid soaking the lower half of the shock/strut and surrounding parts, or dripping from the unit does. Checking for worn or loose mounting bushings in the suspension and strut mounts, and worn upper bearing plates can also identify causes for poor ride and handling.
Here's today's reality. If you plan to keep a typical mainstream, average-priced vehicle for 150,000 miles, anticipate replacing the shocks/struts at roughly "half-life" — around 75,000 miles.
One additional thought — has the vehicle been involved in a significant crash? If so, residual damage, poor quality repairs or bent suspension/steering components could be a factor.
Q: Our 2008 Hyundai Santa Fe has the 2.7-liter V6. Everytime we fill the fuel tank, the engine floods, making it a hard to start and keep running properly. It takes a few minutes to overcome this problem. We have tried partially filling the tank but that didn't have any effect.
A: Focus on the EVAP system — evaporative emissions control system. As you fill the tank, fuel vapor is collected in the charcoal canister. When you start the engine, the ECM opens the purge control solenoid valve, which applies manifold vacuum to the canister to mix the trapped vapor with air and draw it into the combustion chambers to burn.
If this valve is leaking or stuck open, or if the canister is filled with liquid fuel from overfilling the fuel tank, the engine may flood during refueling. A scan tool can identify specific faults with the EVAP system and valves.
Q: I have a 2008 Honda Pilot with 68,000 miles. Recently the "Check engine" light illuminated and a local shop read a P0420 code. This is "Rear bank catalyst efficiency below threshold." This is my third Honda, each having been driven 10 years and over 100,000 miles without a catalytic converter problem. In fact, Honda's warranty on the converter is eight years/80,000 miles. In doing research, it appears this code is not unusual on many cars. I have learned that it may not be the catalytic converter, but rather something about the fuel-air mixture or exhaust being abnormal. I want to take this to the Honda dealer and would appreciate any advice on what to say to them in case the service writer just wants to replace the converter.
A: Honda's troubleshooting guide for the P0420 DTC fault code includes a specific note indicating that poor fuel quality can generate this code, and to troubleshoot and clear any stored oxygen sensor codes before proceeding. Their diagnostic tests involve driving the car under specific conditions while monitoring the OBD status. The results can be "passed/intermittent failure, or failed." If the final result is "failed," have the specific converter in question replaced under the federal (not Honda) eight-year/80,000-mile emissions warranty.