Last weekend I was driving to work. While driving about 80km/hr (50mph), my check engine light and oil light came on, then all the guages dropped and it felt like I had taken my foot off the accelerator. I could not accelerate, so I guided myself to the side of the road, stopped and turned my car off. I left it off for a few seconds then turned it back on, and it ran fine.

I took it to the mechanic the next day just to make sure nothing serious was wrong, as I noticed ever since that it since this happened, the first gear change after an acceleration (it's an automatic) it seems to jerk more than it used to. The mechanic could find nothing wrong with the car and thinks it was a fluke.

Things to consider when it happened:
I was not shifting in or out of 4 wheel drive when it happened.
My gas tank was about 1/4 full
My oil levels were fine
I was driving on a particularly rough patch of road (lots of snow on the road)


Anyone have any ideas? His thoughts were I may have had condensation in my tank and it sucked in water, or a rogue piece of ice came up and struck something.

. Check for codes.

. Change the fuel filter. Ethanol accelerates the formation of water in the gas tank. Cold temperatures then cause the water to separate from the gasoline. Since water is heavier than gasoline and the fuel pickup is on the bottom of the tank, starting and running problems can develop. Winter is when most fuel-related problems appear.

. Change the transmission fluid and filter, if it has not been done in 30,000 miles. I would only use full synthetic lubricants in any Canadian vehicle, due to the cold weather. For your transmission, I would use Mobil 1 Synthetic Multi-Vehicle ATF. You should notice a major improvement in upshifts, downshifts, and gas mileage. Using full synthetics in the engine and transmission should increase gas mileage by 8 to 10%.

I'd bet money on a bum ignition switch. Very high failure rate on this era GM vehicles. Also very intermittent when it happens. Only way to test for sure is to check for voltage at ignition switch when vehicle dies. Or, just replace the switch.