When driving a warm car on the highway above 80 MPH or when accellerating quickly, I get a steady build up of fumes inside my car that make me feel like driving when drunk. I think the fumes enter my car when decelerating by letting my foot off the gas completely or when shifting into lower gear (three gear to be exact I have an automatic). But it may happen from accelerating, this decelerating theory was something I was just thinking about.

The fumes don't seem to enter through the air vents, but some other place. Now I have a oil leak that starts from a vacume tube that is under the air intake manafold and goes somewhere where I would have to take the whole engine apart. I don't have the tools for that, so I said forget it. I think the fumes could be the oil burning off of my exhaust and catalayic converters cause they're covered with oil. Only leaks about half quart or quart per 3,000 miles. Also I thought it might be my exhaust because I had to remove one of the catalayic converters and my exhaust sounded loud. I know that removing a catalayic will make the car sound a certain way and also louder, but to me it sounded like there was still a leak when driving or accellerating fast. But standing still I couldn't detect any leaks, since there's not a lot of backpressure. But also I don't think there's a leak because there are no telltale black spots on the exhaust system.

My question is, is this smell oil or exhaust? Like I said I already think it's oil but I can't be sure; please tell me what you think is wrong with my tests if you think it's the exhaust. If you think it's the oil do you know where the leak might be coming from, from my description. Or how can I stop the oil fumes. Like where is the air intake for the cabin for this model Audi. Although I mentioned I didn't think the fumes are coming in through the cabin air intake I can't be sure. I also think it's the exhaust because it smells like an exhaust leak; had two other car with exahaust leaks. But I also think that maybe oil burning and exhaust leaks can smell the same. But to confuse things further, I don't think enough oil could burn and leak into cabin to smell it up that bad, also the smell starts and stops within a few seconds of accellerating and decellerating. I'm not to sure about this though because like I said the fumes make me feels almost drunk in a way.

I hope some one can understand my scatterbrain explainations/thoughts and help me :icon16:

Forgot to mention car is Audi 90S; year 1994; 2.8 V-6