1999 Honda Civic LX that will randomly stall while driving. Sometimes the car will start right up and won't have another problem during that trip but sometimes I have to let it sit for 5-10 minutes. When it initially stalls, I can hit the accelerator and still hear the engine rev up but all other aspects go dead. I have check/changed the main relay assembly and fuel pump with no luck . . . what else could be the problem?

 

Can you recreate the problem if you jiggle the key around when the car is running?

A buddy of mine had a similar problem. He would hit a hard bump or touch his knee to the key sometimes and the car would shut off. Turned out to be his ignition switch. Simple fix IMO.

 

Yeah, I have tried jiggling the key while driving but nothing happens. The ignition switch was replaced about a year ago also. It happened to me today where I pulled in to get gas and didn't get more than 15 feet away and it stalled. Tried restarting it and it took 3 times before it started back up. Was able to drive about a mile before it crapped out on me again.

 

When it stalls, before you try to restart, see if the oil and battery lights on the dash come on like they should when the key is on but the engine is not turning. If those lights stay out the whole system is losing power either from the ignition switch or elsewhere.

Then, during the time when it won't re-start, check if the spark plugs are firing. A common cause of intermittent stalling is the ICM (ignition control module, or "igniter", which drives the ignition coil). They can fail in a way where they stop working when hot but then work again after cooling off.

 

Just fixed this problem on my 99. Its the ignition switch under the steering column. You can get by with using a fresh key, but you need to replace the ignition starter switch. This is the harness that runs from the back of the ignition switch to the harness under the steering column. the rotating contacts wear out. (Orielly auto part # 18-0636), $65.