I recently purchased a 1999 Nissan Altima. The car is in good shape overall, with 84,000 miles at present, but it has a problem I haven't been able to fix.

The engine tends to cut out at odd intervals. When I'm traveling at highway speeds, the engine often "bucks and snorts", like it's either fuel-starved, the plugs are misfiring, or the AT is rapidly shifting in and out of a lower gear. Pressing on the accelerator stops the problem-- the engine will run fine for a few minutes, then it will happen again. It only happens when I'm cruising at constant speed, decelerating, OR, when I come up to a stop light, etc., the engine will often idle for a few moments, then start sputtering and die.

It doesn't happen until I've driven the car a little-- sometimes within 10 minutes, others close to an hour or more. The only constant I've noticed is that it seems to happen more quickly and more often when outside air temperature is warm.

I've replaced the plugs, rotor, distributor cap, and fuel filter. I've also scanned it with my Auto X-Ray scanner, which has real-time scanning capabilities. The scan doesn't show any trouble codes-- the only unusual thing is that the engine inlet air temperature seems to be quite high--- 150-180 degrees.

One troubleshooting guide said it might be the fuel pressure regulator, or the fuel pump; a mechanic thinks its the control module, but I don't want to spend several hundred dollars on a "replace things until it works" effort to solve the problem.

Has anyone else experienced this? Or, any suggestion?

Thanks,

Smitty