Ok so things have been going ok with the truck, minus the gas filling issues,lol but I have noticed that when I am hauling some *** in which i do down a certain road that leads to my house that if I dont make the stoplight and have to break relativly fast say from 60 down to 0 I notice my oil guage drops down quite a bit and that makes the truck hesitate.

any reason this would be happening?, I do not notice this on any other stops I make, its always this same light in which I approach pretty fast when n if it turns red.

Thanks.

 

First off it means your oil level is low enough that when the oil gushes forward during the stop the oil pressure drops. Eventually, it'll drop off so much that your gauge will bottom out a a ding will sound along with a check engine light.

Your plenum gasket is likely blown, and it's sucking oil in through the intake process slowly burning it away internally. To check for this, unbolt the TB, swing it aside, and using a flashlight, peer down into the intake. You're looking for oil pooling on the pan you see at the bottom in the intake.

If you see oil pooling, check the corners too where near the rear two cylinders...you're going to have to repair the plenum gasket. It causes a slight vacuum leak. It fouls plugs #7 and #8, and eventually leads to a clogged CAT which leads to all sorts of other problems.

The problem is that the plenum plate is steel, bolted to an aluminum intake, with bolts that bottom out. The metals contract and expand at different rates, and the gasket is compromised from heat cycles. Eventually, when it goes, it starts sucking in oil.

The simple fix is a new gasket with shorter bolts. Mine has lasted a long time that way. The BEST fix, is an aluminum plate to replace the steel plate, with a new gasket.

At the same time, while the intake is off, it's a good time to replace the T-stat and crossover tube. Some will even go so far in as to replace the water pump and timing chain set...but that would be up to you as to how far in you want to go to replace parts.

Once the plenum gasket is fixed, pull your back two plugs on each side and clean them off. Might not be a bad idea to clean the forward O2 sensor too.

 

Ok I had a oilchange done to this thing so shes full on oil & now the oil guage isn't bottoming out but I notice its going down under 40 ( halfway point on guage) while I brake & it seems when its warmed up that oil pressure is now dropping when Im at a stop, when I accelerate it goes back up to say the halfway point tween 40 & 110, Im confused.

I am not noticing any clanking of rods, or any noise that would indicate the oils not doing what its suppose to do, in fact I was quite low on oil which is why it was bottoming out before on hard stops making the bell ring and I still didn't hear anything from the motor other then normal sound.

I am also starting to think my mechanic is a book mechanic as he doesn't seem to have much knowledge about what problems lead to what problems

 

You'll never know if the readings your gauge show you are accurate unless you test with a mechanical gauge and compare readings.

If both gauges show low oil pressure, it could be worn bearing tolerances or it could be a failing oil pump. Seeing as how oil pumps fail rarely, I would put my money on a bad sender, inaccurate readings, and bearing wear...and in that order, before a bad oil pump.

 

You're not alone on the oil gauge flutters.

SJ02

 

the oil gauge in these trucks is an actual gauge, when you are at idle it will be off center to the left, this is NORMAL!!!!!!!!!!!, while driving or accelerating hard it will be cetnered to the right (or off to the right), this is also normal. As the engine warms up the oil thins out some, thin oil generates less pressure therefore the needle drifts left, as long as you stay between the two main hash marks you have nothing to worry about

for reference i have 25 psi at idle when warmed up and 70 at idle when cold

 

That sounds about where my 5.2 sits at also.

 

Sooper, is burning oil between oil changes (up to 2 quarts every 3000 miles) a symptom of the plenum gasket leaking?

 

Yes sir. If it's not in puddles under the truck in the driveway or garage, then the engine is burning it. The consumption isn't as bad as I have seen, but it's still enough of a problem that it's noticeable, and it's probably going to start fouling #7 and #8 plugs, which will lead to more issue.

 

in proper working condition these engines burn so little oil you should not need to add between changes (i am usually shor 1/4 -1/2 qt when i take it out compared to what i put in every change, i change my oil every 5k miles.