Dear Tom and Ray:

I have a 1983 Nissan 280ZX turbo with 147,000 miles. When I start the car up on cold mornings, there is a loud tapping noise for a few seconds, even though the engine idles smoothly. When I drive it, it sputters and lurches for a good 10 miles, with occasional backfires in the engine compartment. The sputtering seems to happen when I step on the gas pedal. I always use 91 octane, the compression is strong, the fuel injectors were cleaned, the gas/air ratio was tuned richer while I'm getting poorer trying to fix this problem. Please help! -- Susan

RAY: Gee, Susan. I'm reminded of what the doctor says when he looks at my brother. "At your age," he says, "it could be almost anything!" And that's true of your car, too.

TOM: It's possible that tapping noise has nothing to do with the sputtering and lurching. The tapping could be coming from a sticky valve or a bad lifter. And that may have little or nothing to do with the poor performance.

RAY: The drivability problem could be caused by something like a bad coolant temperature sensor, a bad air mass meter, or even partially plugged-up fuel injectors. Any of those things could cause sputtering when the engine is cold.

TOM: I'd start with the sensors, Susan. They're easy to check. And if that's not the problem, I'd seriously consider marrying a Nissan mechanic. That'll save you some money. Or, if you're already married, consider taking one in as an au pair.