Originally Posted by Amydaveg 
Any help would be appreciated before I put this camera on ebay in exchange for a Canon.
I'm afraid what you intended to do is the final solution as it's a typical problem for Pentax DSLRs to underexposue and have inconsistency and worse metering/exposure.
Read my homepage and my blog for more detailed info about the exposure problems, where I have documented all those problems as reported with some systematic analyses. Unfortunately, there is no real solution to the problem except fiddling around with the EV compensation values and look at the histogram closely, after each shot.