Wow, so it was almost two years ago I bought the truck. When I first bought her the oil pressure, once the truck was warmed to operating temp, would drop sometime to half between 40 and zero and the oil light would flicker and if you let is sit and idle it would drop to zero, and the oil light stays on, if you throttle up a little the pressure goes back up. But once you let off of the gas it does the same thing. I had to replace the oil pressure sending unit, and then the oil pump and pickup screen. About a year ago I replace the sending unit again because the problem was still happening. I just don't know where to go from here. If anyone has some advice I appreciate it.

 

I have the same exact problem.

They told me it was a air pocket where the oil drains to the sending unit, therefore going up/down hills or at idle that pocket would fill with air and the sending unit think's there is no oil in it.

Do you happen to have a stick shift as well?

 

No, mine is an automatic. This is weird though, the up and down hill part that you were talking about is not part of my issue. In any case did they tell you how to get the air pocket out? Another weird thing is that I have been reading all the threads on here about oil pressure issues and most peoples are different than ours, their oil pressure is dropping when they step on the gas, so I am guessing that is an entirely different problem.

 

ya they said to bring it back and they would try to fix it... but the truck is my daily driver and this problem does not in any way effect the trucks driving, i mean as far as the motor still functioning properly. they did say it was kinda common on GM pickups as the tech i talked to said he used to work for them.

but that is wierd... i was hoping i wasn't alone haha

 

i bet your oil pump is clogged. It happened to me after I corrected the manifold gasket and plenum gasket. If you investigate the oil pump i bet it will have debris on the tube screen.

 

hmm, i'll check it out next week.

 

My truck has 280,000 miles and burns just a little oil if my level drops some this happens to me maybe this is the same as you next time just change the oil and not the amount you are getting out from the drain!! hope this will help some.

 

Pull the oil pan, buy a melling high volume unit and replace the pump. It's $37 of insurance at Autozone.


Here's some instructions, ignore the stuff about the rear main seal:

http://www.pavementsucks.com/tech/rearmain.php

 

I alreadyh have the melling in there and a brand new pickup and screen the problem never stopped. When I dropped the pan last time there was nothing bloking the pick up or screen, and the damned old pump still worked. So any other ideas, like i said I have also replace the sending unit twice I figured maybe that cheap a$$ part might be deffective from the factory. The only thing I noticed was that when I ran syntec in her it was perfect, then I wanted to give some penzoil synthetic a shot, much to my dismay not only did the problem come back, but I swear my mileage dropped about 15 miles per tank.(An average over 3 months) So, next time I when I change the oil I will flush her good and I am going to run royal, I already switched all my other vehicles and have had great results. I'll let you all know if it helps.

 

A HIGH VOLUME OR HIGH PRESSURE OIL PUMP IS NOTHING MORE THAN A VERY POOR BANDAGE FOR A LOOSE WORN OUT ENGINE. If you have no oil pressure @ idle but have it when idled up the bearing in the engine have too much clearance and this is ware your oil pressureis going.