Chrysler Repair: Oil Pressure, rod bearings, accurate gauge

Question
I've a '98 Cirrus w/ a 2.5L six since it was new.  It has 155,000 mi on it.  It burns no oil and looks and runs like new.  The oil pressure light comes on at low idle when using any oil less than straight 50 weight ... I have had the pressure sender on the front of the motor replaced w/ an aftermarket and that didn't solve the problem either.  I assume that the rings are OK since it burns no oil and runs so smooth and tight.  Does it sound like the rod bearings need to be replaced?  If so can you give me a ballpark of the cost of having the bearings replaced.  Any ideas or suggestions will be appreciated.  Also the Check Engine light comes on.  It seems the best way to keep it off is to use a water remover in the gas tank ... any idea what's up w/ that, I've had it to the dealer and they tried all their tricks and it turned off for a couple days and then came back on, they said they did not know what it needed ... thanks again.  
John

Answer
Hi John,
The spec for oil pressure is 11.4 psi or more at idle with the oil at 167-194F. So I would suggest that you have that read with an accurate gauge. I would first inspect the oil pump if you don't meet that spec before thinking about bearings. Much less expensive too.
I guess unless you can get a readout, which it should do when the light comes on, there is very little to consider as a solution. Try another shop for a readout or even ask at Autozone which others have told me will do a readout for free. Let me know what number(s) come out, if any.
Roland