Oil pressure drop in idle

[Wildxfyr]

I have a 2001 Chevrolet Silverado when I first crank it in the morning it clatters for a good 15 seconds to 20 seconds also after it warms up a little to about 100 degrees and you let off the gas and let it idle the oil pressure will drop slowly, but when you apply the gas the oil pressure will pick back up to 40. The weird part is when it warms up to 210 it does fine it will idle all day long. But if I let the truck set and cool off it will do the same thing until it gets back up to operating temperature I was told the o-ring on the pick up tube could be bad or the oil pump but would like to get a second opinion.

[Nick Bobinger]

I had a similar problem on my 04. It would do well until it warmed up and then at lights at idle I would get a low oil pressure warning. We replaced the pick up sensor, oil pump, gaskets, etc. Still continued to have problems with it. Only thing I could think is it was something with the dash going out or the rings/seals going out.

[certified22]

I got same thing going on with my 04 it's the o-ring on the pickup tube in the oil pan it's only a $2 part unfortunately to get the oil pan off of an 04 Chevy Tahoe z-71 you have to pull the front differential so it's not such a simple driveway job anymore ya gay on top of gay but you can always just replace the oil pump while your at it for about $180 however for this procedure the front of the motor has to come off water pump harmonic balancer timing cover timing gears groeter gears and other miscellaneouses that I may be forgetting off the top of my head you could try just changing out the oil pressure sending unit but to get to it you have to remove the intake manifold and while your doing that you might as well change out the pesky gaskets that have been causing your rough idle when it gets cold out and throwing the too lean banks 1 and 2 codes the random misfire codes and the MAF sensor code I believe they are p0101 p0171 p0174 p0300 and I can't remember the MAF sensor code anyhow that's what I got for you and the trouble I'm having and how I intends to fix it cause that's how the ole boys from this awesome group here have fixed there's and enlightened me on how to fix mine good luck

[Wildxfyr]

Thanks for the input, ive called the guy who does my work for me, to replace 2 02 sensors pick up tube o-ring, and oil pump im looking at $945. I cant run my truck trough the drive through carwash and let it idle without it misfiring. As soon as water starts getting sprayed under the truck it starts misfiring. But clearss up when i give it some gas and keep it at a high idle or drive down the road.

[certified22]

My 04 Tahoe does the same thing when water spray the under carriage it sprays up in the air cleaner box and gets your air filter wet that's what causes the misfire usually clears up with a little throttle before the car wash is done next time you go thru the wash just go fast over the engine compartment and it won't happen if your truck is same as my Tahoe you should have 4 O2 sensors two up stream two down stream but don't let the idiot at orreilys tell you they are different or the down stream are factory only or they will have to order them because they are all four the exact same part part number everything and I don't know how much of the 945 $ is going toward the replacement of the O2 sensors but u might ask cause you can get them yourself for about 30 dollars a piece the O2 sensor tool is 10 or you can make your own by cutting a notch in a socket I just bought the tool and mine didn't require it but never hurts to soak them in panther piss or pb blaster before you get started and they are really easy to change out yourself I did all four of mine in about 15 20 minutes and that's with my OCD kicked in high gear scoping out everything I think might look out of place lol and no creeper might save you a few dollars might not your mechanic might be throwing them in with the price of the oil pump swap cause it's no quick simple task and the local Chevy house here quoted me 1400$ to change mine out and 1900 $ to just change the o ring in the pan cause they was gonna have to pull the front differential I was like you people are high if you think I'll pay that much I fortunately come from a long distinguished line of Chevy mechanically inclined beer drinking good ole boys and can do this job on my own I was kinda hoping to get to be lazy and maybe pay some one else to do it for 2 or 3 hundred no such luck unfortunately so I guess the honor is all mine lol

[Wildxfyr]

Lmao, yea i thought i might get by with a couple hundred $$ to. Yea i come from a long line of mechanics myself every guy in my family is a mechanic I used to do it but I got into the trucking industry so I Drive 18 wheelers I don't have time now and you as soon as I go over the sprayer on the engine compartment it starts that misfiring

[raja]

Oil pressure dipped on cold mornings but once warm stayed above zero. No ding ding ding...

Had dealer diagnose they said oil pumps going out. Called local call in show, they've done several and it's the oil pickup tube o-ring. Four hrs of shop time and 40 lbs at highway speeds.

[Daniel123]

Ok got 2002 z71 5.3  new oil pump 

had good oil pressure after I got it started then it dropped off and now 

it started no oil pressure at all but if I drive it pressure goes up to 20 mayby but then stays at about 12 

I think wrong o wring 

[Hector J]

I have 2008 5.3 silverado , had oil pump replaced with a high volume pump after a while pressure stated to drop but stayed above 20. drove on a delivery about 900 miles lost all oil pressure had it towed to a chevy dealer they said I had a collapse lifter had it truck ship back how had liter replaced. started truck up it was above 40 but after it warmed up it drop below 20. also replaced oil sending unit and screen 

can any one help