Q: I own a 1995 Pontiac Formula with the LT1 engine and 6-speed transmission. The problem that I have is that the car shuts off while driving. This happens regardless of whether I'm idling or driving. It also occurs regardless of whether it's hot or cold outside, or the engine is warm or cold. The problem is intermittent and sometimes doesn't occur for three weeks. We replaced the fuel pump and fuel filter, and the problem is still there.

When the car dies out, it does not start back up immediately. It will eventually start back up after it has sat for about 30 minutes. I noticed that if I turn the key on after the engine shuts off; I couldn't hear the fuel pump. But, if I turn the key on/off several times after it has died out, I can get the fuel pump to run and get the engine started. But it only runs for about a block and turns off again. The dealer had the vehicle for two days and couldn't replicate the problem. I'm wondering if you have any ideas.-- S.M., Elmhurst

A: S.M., intermittent problems such as yours can be challenging and difficult to solve. I don't think that your Formula's engine is stalling as a result of a fuel delivery problem, though. Usually, when the fuel delivery system is acting up, the engine will lose power and stumble, operating like it's running out of gas. Your description that the engine just shuts off leads me to believe there's either an electrical problem with the ignition system or the Powertrain Control Module (PCM).

The PCM could be shutting off the fuel injection system because of an internal fault, or if there's a problem with one of its many sensors or electrical circuits. You'll need to find a repair shop that employs a technician that's skilled and patient enough to diagnose your car. The technician will need to determine if the engine is losing fuel injection pulses and/or spark to the spark plugs. A spark tester (connected to a spark plug wire) and lab scope (hooked up to the fuel injectors) will allow the technician to see what's happening. And once the engine stalls, the technician will be able to see which system (ignition or fuel injection) gave up.

The service information for your vehicle has a diagnostic flow chart that the technician can follow once the engine stalls, but obviously, the problem has to occur for the technician to figure out what's wrong. You should be prepared to leave your vehicle with a repair facility long enough for them to experience the engine stalling.

Q: I'm having trouble with the power windows in my 2004 Mercury Marquis. Both front power window motors have been replaced and I'm still having trouble with them. What could be wrong?-- K.K., e-mail

A: K.K., if the front windows are not working properly, but the rear windows are okay; I would suspect a problem with the driver's master window switch. There are many circuits that go through the master switch; so it's possible that part of that switch could be faulty. If the front window motors have been failing frequently, I would suspect something is wrong with the window regulator or there's an alignment issue inside the door. You might consider finding an automotive glass shop that could solve your trouble.

Questions for Ira Siegel? Call the Auto Adviser Hotline at 708/633-6839 or e-mail Autoadvisr@aol.comAutoAdviser: Ira Siegel is an Automotive Instructor and ASE Certified Master Auto Technician