As some of you know, I have had a hard time getting my truck (04 F150, FX4, 5.4, 98k miles) running right. A few months ago I changed plugs, fuel filter, anc cleaned TB and MAF. It ran perfect until a few weeks ago when it gave me a CEL light and two lean codes. It will stall and die if left idling in park. I am taking it to a shop Monday to find out whats up with running lean and dying. I also had a driver's side oil leak. Mechanic told me it was the valve cover gasket, but it was not. I assumed it was leaking from somewhere else until I pulled a small trailer about 50 miles this week. After about 30 miles, I could notice smoke in my rear view when going up a hill or when I accelerated. When I let off, it would quit smoking. It is coming from under the truck (not from exhaust), and when I stopped the truck, oil was dripping from the undercarriage, and was all over my tailgate and the trailer I was pulling. In the 100 mile roundtrip, I went through about 1 1/2 quart of oil. I also noticed a small amount of oil in the intake back when I changed the plugs. Can anybody tell me where the oil might be coming from? Thanks in advance, Jake.
I'm thinking MAF sensor is the problem with the stalling and lean codes. My bros truck did the same thing and that was his problem. If oil is dripping, then there is a leak somewhere. Since you can't see it above the engine, I'd assume maybe the rear main is leaking. I don't see it having blow by with less than a 100k.
And you are sure that it is not a valve cover? Notice any funky readings on your oil pressure gauge? The sending unit on my dd sprung a leak and it was spraying oil everywhere. The gauge showed low pressure when it happened, though.
Pretty sure it's not the valve cover. I changed the gasket, and there was no sign of oil leaking from it. My oil pressure actually stays right above the midpoint on the gauge no matter what. I've noticed before that it doesn't go up when I accelerate. When you crank the truck, it goes to the same spot and doesn't move until I kill the truck. Do you know where it is located? Thank you.
That gauge is just an idiot gauge. It shows the exact same reading over a wide pressure range. Drop below the minimum for the sensor and it will fall to nothing. The sending unit should be down around the oil filter on these trucks. Speaking of oil filters... it isn't leaking, is it? Sometimes the old gasket sticks to the block and they accidentally get left on there. That causes a leak almost every time.
