intermitent ignition failure

[ebgbz]

1999 Pathfinder, 3.3, 2wd.
Recently experienced engine running very rough...and failure. It would start, run rough and then die.
At the shop due to this occurring they couldn't replicate the issue. I'm at a loss because it has occurred twice both times requiring a tow.
Anyone experience this? Is it distributor related or some other ignition thing?

[mdmellott]

Start with the basics. Distributor cap and rotor contacts should be checked. If there is any sign of ark ware down of the contact points inside the distributor or the rotor, replace them. These are routinely replaced parts as needed. Also, check the distributor wires for proper resistance, particularly the center wire. Check the coil primary and secondary for proper resistance. Coils don't last forever. The only other intermittent failure issue I have seen, that sounds like this, is a faulting alternator. It should be putting out a consistent >13V. If the voltage output is sporadic and dropping below 13V, its time to replace the alternator. It sounds like you are describing an ignition issue. These are the only intermittent causes I can think of aside from a loose or contaminated cable or wire contact, or which there are many to check.