Check Engine light on,p0306 code

Good call, I got a #4 misfire and turned out to be exhaust valve, (recessed seat). She began misfiring at 210,000mi. Found rebuilt heads with tungsen carbide exhaust seats on eBay motors.

Thanks for the input guys,i just found out last week the truck is an E-85 ethonal burning setup.Have run a couple tanks of corn syrup with no change-except cold startup is much takes a lot more effort.Also a fellow mazda b3000 owner heard the critter cage chirping under the hoodand went on about the shaft where the distributor used to be causing my noise,and said it would cause engine codes from worn bearing-timing sensor issues,anyone heard of this?

Yes, that would be a worn synchronizer. Kind of like a distributor.