My son owns a 93 Regal 3.1 V6 that won''t stay running longer than about 3-4 minutes.

Last year it began stalling at lights and occasionally missing while driving. Then one morning it refused to start and stay running. We flashed out the codes and the indication was a fuel system issue plus a MAP (Manifold Absolute Pressure) sensor but this vehicle has no MAP sensor, only a MAF (Mass Air) sensor.

We replaced the fuel filter and fuel pump/strainer and it started right up and ran fine for about 4 minutes. Then it died and won''t successfully stay running. When it does start it seems to be cross firing / misfiring. I see pronounced PCV regurgitation indicating the firing order is messed up.

My experience is on older vehicles so I''m not familiar with the DIS ignition system or how it works but it sounds very much like a wet distributor cap causing cross firing of cylinders. But, this engine has no cap so I''m a bit lost.

My suspicions are:</span>
<div style="margin-left: 40px;">Cam sensor
Crank sensor
ECM power / faulty wiring
Some other sensor related to closed loop operation
</div>
Any ideas?

My suspicions are:</span>
Cam sensor
Crank sensor
ECM power / faulty wiring
Some other sensor related to closed loop operation
I think you are on the right track.