Q I have a 2009 3.5-liter Nissan Maxima with 39,000 miles. Recently I filled the car with 16 gallons of premium fuel, drove about 50 miles and returned home. Later that day my car wouldn't run. We discovered that the fuel tank at the gas station had been filled with diesel fuel. My car was repaired at a Nissan dealership. Repairs and out-of-pocket costs will be reimbursed by the gas station insurance. How concerned should I be about the possibility of issues developing later that would affect my car's performance or value?
A Very little. As long as the diesel fuel was completely flushed from all parts of the fuel system, I don't think there will be any long-term mechanical or drivability effects. In my opinion, there should be very little if any long-term impact on the vehicle's value.
Q My '98 Nissan Quest has had a fuel odor for years and it's driving me nuts. My sweetheart won't ride in the car any longer. My shop had it analyzed, but it shows only a code for intermittent odometer operations. They did a pressure test on the gas line, dropped the tank to check all connections and replaced the short 90-degree rubber tube coming off the top of the tank on the driver side. They've inspected with flashlights from back to front without success.
A Use the sniff test to try to pinpoint which end of the vehicle the odor is coming from. Nissan had an early recall for a possible fuel tank vent hose leak, which would orient the odor to the rear of the vehicle. A leak from any of the evaporative emission system components or charcoal canister would make the odor most noticeable under the hood. In addition, consistent "fuel packing" -- continuously pulling the handle on the refueling nozzle to squeeze in the last few ounces of fuel into the tank -- can force liquid fuel forward into the canister, which is designed to store fuel vapors until the engine is started. Checking the weight of the canister can confirm whether or not it is filled with liquid fuel.
I'm a bit wary of the diagnosis and tests you've had performed. I checked my ALLDATA automotive database and do not find a specific fault code for an odometer issue. There are codes for issues with the speed sensor, which is a key input for engine management. As always, it's important to note the specific DTC fault code detected by the scan tool.
Q I recently purchased a 1999 Lexus RX300 AWD, with 131,000 miles, that has been very carefully maintained by the one previous owner. When I first start out on chilly mornings, I notice that the automatic transmission stays in second after shifting up from first until the car reaches nearly 40 miles per hour. It stays in second even if I can feel the transmission drag when I back off the accelerator to slow down. It doesn't shift up to third until it's over 40 mph or until it warms up, which is usually within a mile or so. Is there a sensor that tells the transmission when to shift based upon temperature, speed and rate of acceleration? If so, should I have a technician diagnose the problem or does this sound like normal operation for this make and model?
A Carmakers program transmission control modules to hold lower gears longer to aid in warm-up of the vehicle's lubricants and the catalytic converter. Doing so reduces emissions and fuel consumption by bringing the vehicle up to full temperature and "closed loop" operation quicker. In this case, rather than the second-to-third shift, I suspect it's the delayed third-to-fourth/overdrive upshift that you're experiencing.
It's one of those characteristics that doesn't feel very good but isn't doing any harm.