If it is intermittent check that the cables from the alternator are secured. I had that problem with my truck I had. Turned out I forgot to tighten the cable from the alterantor back down, while doing some work.

 

This is why I always recommend that you get and install a volt gauge so you know what is going on all of the time instead of relying on an idiot light which doesn't come on until it's too late. I also highly recommend that you install an oil pressure gauge for the same reasons, and the oil light won't come on until it drops below 3 psi, now how scary is that. By the time the idiot lights pop on your already screwed.[] I was horrified that the SRT-4's don't even come with an oil pressure or volt gauge, so I have both gauges from the ones I installed in my '99 Neon R/T to install in my SRT-4.

 

good idea mango..