I am interested in buying a car from a private seller who claims an Audi A4 1.8 liter Quattro is in perfect condition other then needing a Mass air flow sensor. What is that exactly and could there be any other potentially problems? He lives about 2 hours away and is it hazardous to drive back home with a repair issue?
I would be cautious. Some imports use a airflow meter/mass airflow sensor that is in the air cleaner snorkel, they can cost somewhere in the range of a $1000 to replace.
He is actually claiming the costs to be around $200. I am interested in 2 Audi vehicles, one A4 1.8 Turboneeds a timing belt(supposedly) and the other Audi A4 1.8 Quattro needs a Mass air sensor, I am not sure of there functions and if it is worth buying…
The MAF tells the car’s computer how much air is coming in an then the computer decides how much fuel it needs after consulting a number of other sensors. They have a default mode, and that may be what is happing now, It will loss power and mileage while in default mode. You can call any dealer or many local independent mechanics to find out the cost of replacing one. It may just need cleaning, especially if it had a K&N air filter on it.
In short, it should dive back but it will not drive well. I should not cause any other damage.
This is interesting…Two posts the same day with people buy a car and the car needs service…Both are Audi with the 1.8l engine. Something about Audi owners who don’t want to get the car fixed BEFOER they try to sell it???
If you are interested enough find/pay a local to car qualified (import) mechanic to look the car over before purchase. In the process you will get an estimate of the repair price not a made up price if your uncle Louie pulls a part out of the junkyard and installs it 
In checking the codes their may be more problems present and you will get a true evaluation of the car conditions. Your buying a potential nightmare. Audi’s with 1.8T’s require a timing belt change somewhere between 60k-105k(depends on year) and this is a $600-$700 maintenance item.
If you own a perfectly running 06 Accord posted elsewhere why on earth would you buy an old car with potential issues blindly?