I have a 99 Camry V6 LE w/ 285,000. Over the last few months it has developed a "stutter" that appears randomly where the car suddenly 'lurches" a few times as if the engine cut out for a split second (or the clutch slipped). Maybe related I recently had the engine check light come on for low Cat efficiency , but that went out after I ran a can of STP Injector cleaner on a tank of fuel. Cat has 44K miles on it. Seems to happen when the engine is cooler, in fact today I made a 200 mile trip and experienced the issue just after filling the tank. Eventually it stopped and had no trouble for the rest of the trip. Sometimes it happens after the idle slows down and stalls after sitting at a stoplight. Otherwise it runs like a top. Maybe related a new fuel pump was installed a few months back. Mileage is great, 28-30 highway, oil is clean, coolant levels stay up, engine temp is steady. Any thoughts or guidance welcome.

 

If engine is stalling when foot off the throttle try cleaning the idle air control (IAC) valve attached to the throttle body. The internet has post on doing this.

 

Thanks - will give that a try...also found some posts with similar symptoms pointing to electrical issues - maybe alternator problem, plug wires or battery connections...started by cleaning terminals and posts which were both slightly corroded and dirty.