Engine - possibly burning oil?
 

2004 F150 V8, around 110,000 miles on it.

About a year and a half ago (around 95,000 miles I believe), the check engine light came on... took it in for diagnostic and derr, poor thing had practically no oil in it. Mechanics kind of laughed at us and gave it an oil change. We deserved it, haha.

Yesterday, same thing - service engine light came on, boyfriend immediately jumped out and checked the oil. Dry again. Filled it up with almost 5 quarts - he's driving it this morning and he says the engine is acting funny - the RPM would go higher, but the truck was not accelerating. He said it happened a few times and then so far, it has quit. He said it felt like it was sticking somehow.

We'd like to get a lot more use out of this truck, however... if it's not visibly leaking oil anywhere, and yet running out of oil, does that mean it's burning the oil? I've read a little bit about engines burning oil and there being smoke/etc that accompanies this. I'm not sure what "burning oil" means, and this truck doesn't seem to be smoking or putting off a weird smell when it runs. For the most part, it runs great. It does have a weird idle lately, while idling it will go up and down with RPMs but we figured that was some kind of fuel system issue.

Sorry, kind of rambly. Anyone have the same experience/offer advice?

Burning oil refers to when oil leaks past the piston rings into the combustion chamber, therefore burning the oil. Usually it will smoke pretty bad, or at least noticably.

As far as the funny idle, it could be many things. Have someone hook a code reader to it and see if any codes come up.

And out if curiosity, how often do you change the oil?

He usually changes it around 5,000 miles. I'm pretty sure it was due for an oil change this time too, and he's been driving it 70 miles a day for a while now.

5Qts is ALOT even for between oil changes and i mean A LOT!!! you have an issue some where, when you take off the oil cap does it have a milky residue on it? (if so your looking at head gaskets) is there any oil in the coolant? Have a compression check done on the motor, oil HAS to go somewhere and like previously stated if its burning there should be some smoke from the tail pipe

And what motor is in the truck 5.4l? 4.6l?

If its the 5.4, it'll hold 7 quarts.

It's a 5.4l. I drove it around over the weekend and although the oil level is staying the same at the moment, it's now shifting hard out of 1st gear which is a new development.

I'm taking it in tomorrow to have the engine compression test done. There was no milky residue, not sure if there's oil in the coolant yet. I'm crossing my fingers.

....and it just threw a transmission fault light on the way to school tonight.

For the love of eff, I am so disappointed with this truck.