Fuel pressure issue at 5k

Hello Everyone, I have a 1981 KZ750 LTD with around 18,000 miles on it.
As I have been riding lately, I have noticed the occasional feeling of hesitation, especially when accelerating around 5 thousand RPMs. It was tolerable, and I chalked it up to a bad jet or something in the carbs, hoping it would work itself out, I continued riding.
Today, It happened again, repeatedly, and every time i felt it hesitating the low fuel light went on for just a second,(Bring on the Fuel light harassment) coinciding almost exactly with the hesitation.
Is this likely a petcock issue?
I have more than 2/3 of a tank of gas, and no apparent fuel line leaks.
Any Suggestions?
Thanks Guys,
Mike

Recently I had some issues with fuel starvation (at all rpms) and found the problem to be a clogged gas tank cap vent. This was causing a vacuum in the tank preventing adequate fuel getting to the carbs. Cleared the blockage and helped a lot. Not sure if this is your problem, but worth a check.

Thanks, this seems like a possible solution, it has started happening at lower rpms now too.

I am going to post this problem in the electrical section of the site, I think that the real issue might not be fuel, but rather an electrical problem. Last night, I turned the on/off switch and the whole bike powered down, not just the ignition, any ideas?
Anyone have any ideas?