I have a 98.5 B5 2.8V6 Quattro.
gas milage is 19 in town and 24 on freeway.... is something wrong?!?!?!

nope. thats a little low for freeway but i get 18-19 in town

Hmmm I'm averaging 21-23 mpg and my daily driving is 80% freeway.

...........

What am I doing differently then? I average 22.8 city and 28 highway, and about 24.6 mixed...

And that's with an occasionally heavy foot too, depending on how quickly I need to get where I'm going.

Pffft 30 valvers.... I really wouldn't be too concerned other than a good tune up. The variances occur on every forum with every car. There was one guy on here getting 10-12 mpg now that is a cause for some worry.

I average 20-21 in mixed driving..

the most i ever get is 21-22 mixed.
i could probably get up to 26ish HWY if i really tried.
MY AVG IS PROBABLY 16-18MPG; most if not all city driving and i have a heavy foot,
i can get it in the 20's city if i really try...

Same here on my 99 Q2.8 auto...

about 16-18 in city but I do 90% freeway and get 22-23 out of every tank running low 87 octane or mid 89. My engine is 60k miles with a full fresh overhaul (plugs, wires, filters, belts, pullies, fluids...)

Seems about right for what others are saying. My wife's A6 avant gets right in the same range too with 145k miles

I always use 89 octane Fuel and been getting 24-26 on Hwy and 17-20 in city.

I seafomed my car 2 weeks ago and been getting 29 on Hwy and 23 in city.

Using your dash computed MPG doesn't work. Its usually 20% higher than it actually is. So if it says you get 28mpgs, you actually get around 22.
The average for the 2.8L (A4) is about 19 city, and 24 highway. So i would say yours is normal. You might have a small vacuum leak, but nothing major.