Oil pressure problem

[Harleroy]

I've got an '88 Ranger with a 2.9. When I bought it, the motor was in pieces. I put it together with new parts and it ran great (for 30,000 miles) until a few weeks ago. I came off the highway and rolled up to a stop sign and my oil pressure light started flickering. A little higher RPM and it goes out. I changed oil and filter (it was near due) and used 10W40 like always. I still have the same problem. I'm laid up due to rotator cuff surgery so I took it to a mechanic for him to check/change the pressure sending switch. He put a gauge in it and said there's not enough oil pressure after the engine gets up to operating temperature.
Where would you guys go from here? New oil pump? If so, can that be done in the truck? If so, what's involved? Not the oil pump, what do you think it is?

 

[mhughes165]

its a ranger 2.9.....they do that, if u didnt have suffiecient oil pressure then u would be noticing it more, did he actually give u the numbers for it, install a cheap mecanical gauge....

 

[Harleroy]

I was wondering if it was a 2.9 thing. It runs great and doesn't make any funny noises like it's out of oil. I"ll do like you say and put in a gauge and then I can watch it for sure and not just trust the light.
I was also thinking about setting up the idle a tad but was wondering about changing the output of the TPS. Mine is set at 9.0 volts now on the green wire. That's about right, sin't it? Would it screw things up if I dialed in some more idle RPM?

 

[IMenriched]

Main reason for loss of oil pressure is from cam bearings getting wore/too much clearance...understand it was rebuilt ...fairly resently. was the cam bearings done?

new cam? new bearings (rod and main) at the time of rebuild?

also were the rocker arm shafts cleaned out, they tend to fill with sludge?

 

[Harleroy]

This guy had bought everything new to put the motor back together. I know the cam, rod and main bearings were new. The crank had been turned, the cam was new, he bought new heads, he bought new pistons and had the block bored, he spent a bundle on this motor. He tried several times to get me to assemble the motor but I didn't have the time then. He took a job in Florida and had to well the Ranger in a hurry so he offered it to me with a new set of Michelins for $600. I figured it was a pretty good deal so I found the time to put it all together and it's been a pretty good truck so far.
I'll put an oil gauge in it when my shoulder gets better and watch it for now.