I inherited this car from my parents a couple years ago with about 80,000 miles. It ran great for awhile, then the air conditioner and the gauges would quit working while driving. After a few minutes they would resume working and everything would go back to normal. Now it will start sometimes and will not start at other times. I have replaced the battery two times and it seemed to help for a short period. I have had several mechanics look at it. After checking the code and replacing a fuse or sensor and replacing the ignition switch the car is still doing the same thing and no one has a clue what is going on. It seems to me that it may happen more often when going over a bump. Do you know what could be causing this?
Sometimes, crazy stuff like this is caused by a failing BCM (body control module). A new one must be mated to your car. They’re not too expensive.
By not starting, do you mean it won’t crank? Or it cranks ok, but won’t catch and run. If the first, it could be something as simple as a failing neutral safety switch. The definitive test for no-crank is to measure the voltage at both terminals on the starter motor during attempted cranking. If both are above 10.5 volts (measured from terminal to starter case), and it won’t crank, the problem is usually the starter motor needs to be replaced. If either is below 10.5 volts, work backwards to find out why.