A Perhaps the shop can connect a data recorder to the diagnostic link and have you drive the car until it stalls. They may be able to download the data at the time the engine stalls and determine the cause of the shutdown.
A continuing problem with fuel pressure could obviously cause stalling, and if it were a mechanical issue it may not trigger a fault code. It's worth checking the accuracy of the coolant temperature sensor, for example, because an inaccurate signal could cause stalling without recording a fault code.
If the stalling occurs only when the engine is fully warmed up and idling in gear at a stop, a low oil pressure signal from the oil pressure switch on the engine may be shutting off the fuel pump.
Q We have a 2010 Nissan Maxima that has a feature that raises the steering wheel when the engine is shut off. At least three times in the last eight months it has failed to drop down into position when the engine is started. Thankfully, a switch on the column also can be used to reposition the column. We're nearing the 36,000-mile warranty expiration and are glad it's documented with our dealer, but we're concerned about this. Any ideas?
A The automatic tilt function of the steering wheel is part of the automatic drive positioner system, which is integrated with the driver seat control unit. If the driver's seat moves into its memory position correctly but the steering wheel fails to tilt down into its memory position, the harness, connections or automatic drive positioner system module are suspect. A scan tool may be able to pull a specific fault code identifying the problem.
Q I have a 2006 Cadillac CTS with the 3.6-liter V6 engine and 75,000 miles. If my car is not started for several days it will stumble and run very rough for about 10 to 15 seconds and will display a "misfire" code almost always from cylinder 4 and sometimes both 4 and 5. I have found that if I connect a trickle charger to the battery I can leave the car set for weeks and do not have the problem. I recently installed a new battery, but the problem persists.
I have also connected a highly accurate DC ammeter, and with all systems off there is a 0.03-amp drain on the battery. If the car is started every day, there is no problem. Do you think it's a fuel problem or a coil problem? What is a reasonable battery drain on a parked car?
A That's a tough one. Connect a voltmeter to the battery, then start the engine and monitor the battery voltage closely. Voltage should climb into the 13.5-to-14.5 range very quickly, indicating that the alternator is coming on line and voltage is adequate to operate the engine properly. You could also swap coils to different cylinders to see if the misfire follows the coils. If the misfire still occurs in the same cylinders, those fuel injectors may be clogged. GM recommends using its upper engine and fuel injector cleaner through a special injector cleaning tank -- not through the vehicle's gas tank -- to address this potential problem.
In addition, a 30-milliamp parasitic draw on the battery is well within the normal range.