Low-zero oil pressure

What is your question?

This issue began last January, 2010. I relocated to a cold climate from the tropics of S Florida. First day out on the road, I lost oil pressure and the knocks began immediately. I had it towed to a service station. After the 'Lecture' I got about proper and frequent oil changes, the mechanic went about looking for the problem. A few days later I got a call from him saying the pick up screen was clogged (Another lecture). 1600.00 later I picked up the car and the issue seemed to be resolved. From that point, I changed the oil religiously at jiffy lube and also used their oil system flush thingy too. Everything seemed to be alright until a couple of weeks ago (12/2010) when the oil pressure thing came back. Back to the mechanic I went (Another lecture). This time the pressure gauge was moving up and down from Zero to the low point on the gauge. I believed it might be the pressure switch and had it replaced. That did not resolve the problem and back it went to the mechanic. This next visit was to replace the oil pump. It was a very big job. Once inside the motor, they found the timing chain guides disintegrated and the tensioners needed replacing. Those parts and a new oil pump were installed. After all that pressure is still low. The question is, should I try auto-rx to get rid of the sludge and look at the pick up screen again?? I can't afford to walk away from the car right now