1994 olds 98 Regency

3800,V6 cylinder.approx. 77k miles. Car stalls after running for about ten miles. engine jerks and dies, will not restart until engine cools down. If engine does not die after the jerk, has a miss on one cylinder. Once engine cools down, engine runs smooth (no miss). Always receive cam position reading from computer. Have replaced plugs, plug wires, cam sensor, harmonic balancer, computer (2 times),air flow sensor,checked wire harness for shorts,gas line pressure is steady,will idle smooth for approx 30 min but eventually dies. My mechanic has been trying any possibilities without results for the past 6 months. Please help me with this mind bending problem.

The problem might be with the Crankshaft Position Sensor.

This sensor reads off two ring segments on the harmonic balancer. One is called 18X segment because there ar 18 equally spaced windows on the harmonic balancer. The other is called the 3X segment because there are three unequally spaced windows on the harmonic balancer. The ignition module determines which coil to fire depending on when the 18X and 3X signals ocurr during an engine revolution. One of the things that can effect a crankshaft position sensor is engine heat. If the 18X or 3X signal is lost from the sensor, it can cause a misfire. Or if both the 18X and 3X signals are lost from the sensor, the engine will shut down.


The first thing that comes to mind when it is a heat related problem like this is a defective ignition control module.

Here’s what I don’t understand… If it acts up consistantly, why isn’t it being diagnosed when it is in the no start condition? When it doesn’t start it can be checked for a no-spark condition,no fuel pressure,or a lack of a injector pulse. This problem shouldn’t be that hard to diagnose. You need someone else to look at this car. Seems to me the person who is working on it now is just throwing parts at it and hoping the problem is fixed.