my 1993 f250 7.5l oil pressure guage dances when in drive and reverse. when in park or neutral it levels and stays right in the middle. which is normal. my question is... could it be the sending unit or do I have bad cam bearings?

 

when gas is applied it also levels out. only at idle apologies

 

Hook up a rear gauge and not an idiot light and see where the pressure is at on the truck. If it is over 7 psi at idle then it could be the sender, if it is under then it could be the pressure is so low that the engine can run fine and get oil everywhere but the sender is bouncing off and on thanks to it.

 

I will try that. can an oreillys plug this up or will they use idiot light

 

Your best bet is to rent an oil pressure tester from an auto parts store, thread out the sender that is in the engine now and thread in the tester, Once that is done you can start it and see where it is at at idle speed.

 

Yep. Or if you happen to have a 0-100 PSI pressure gauge you can just use that if you can adapt it to the 1/4" female threads in the block.

Factory oil pressure sensor is just a pressure switch that causes the gauge to read "somewhere" in the Normal band, or otherwise read low. You can search on here for how to convert it to a real gauge.