Lately I've been getting terrible gas mileage, and I could feel some hesitation in the throttle. I have a bad habit of letting the gas level get down to almost nothing before adding more, and I thought that, along with the fact that my air filter is old and dirty, and I need an oil change, were causing the poor gas mileage and performance.

However, I popped the hood just now, and found the air filter laying in the engine bay instead of on the MAF. Now, I like to drive hard and fast. So, I'm worried that I may have f'ed up my MAF sensor from all the dirty air flowing directly at it. Also, I'm wondering if now my TB is coated with filth (I'll have to take a look).

But something else I found concerned me even more. The block and top of transmisson are coated in oil. My DIY oil catch can has a significant amount of oil in it (it never has had more than maybe 1 or 2 drops). Plus, the bottom cap is missing, so I have no idea if there has been more oil that leaked out of the can. I'm wondering if the oil everywhere is a result of the air filter being off, or another problem. I haven't noticed any smoke coming out of the exhaust, except the normal little bit when I first start it up.

Also, I have no clue if all this hysteria in my engine bay threw a CEL or not, cause it's permanently on. And I should mention that the car has probably at least 120,000 miles on it, however I don't know the actual mileage cause the odometer stopped working at 67930 miles about 2 years ago or so. So, it's old, and quite honestly I'm surprised it hasn't pooped out yet.

Here's some pics I took of the oil spill:

 

the oil can wont leak even with cap off.. you have to depress that pin to let the oil out..

looks like your valve cover gasket may be leaking. since its above the head gasket that has the oil on it.

 

Hmm, well it's a fairly new gasket. Also, would it just start leaking like that all of the sudden? I've never had it leak before.

 

If the oil return gallies in the head are blocked/restricted it will cause the oil pressure in the head to get high which would account for the oil leak from the cover and the oil in the catch can. You won't see any diff in the engine oil pressure as that is taken from the block.

 

Hmm, well is there any easy way to unblock them? I wish I had an oil pressure gauge.

 

Yeah, looks like your valve cover gasket to me too. Looks like it started leaking at the cam seal and spread probably.

 

Well I guess I'll have to put a new one on it then.

Howabout the MAF sensor, how sensitive is it? Would a ton of air flowing quickly directly at it damage it?

Now wait, what caused the oil pressure to rise? Could it have been from the increased and unsteady airflow?

 

Air flow will not damage the MAF but if the air is dirty that might.
Increased air flow won't do anything to oil pressure.
The suggestion I made concerned the oil return gallies, which are the holes in the head that the oil flows through to get back to the pan. If they were to be blocked the oil would get pumped upto the head but not be able to flow back so pressure would increase and have to vent somehow.

 

Ok, I see what you are saying. So, is there anyway to unblock them? Any sort of treatment I could run through it, or would draining the oil clear it? I'm gonna try changing the gasket first and see if it fixes it.

 

Seafoam would probably help alot. Read the directions on the can as far as your oil is concerned. I think it is 1/3 can into your oil, you run it for 5 minutes or so, then drain the oil. I could be wrong though.