89 Corolla Sr5 Problem, Gas & Lack Of Power

[codyjCA]

heres my short story:

last year i got my first car, 89 sr5 rolla, automatic, and it started out getting like 290 miles on a tank, **** ruled, but now i only get like 190 b4 my fuel light turns on. I dotn know whats up with that, also the car is pretty damn slow at accelerating from a stop, i want to make my car faster cuz i just cant really handle that slowness, what do u recomend would be the best modifications for the price, i was thinkingh about booting up a header from eBay http://cgi.ebay.com/ebaymotors/ws/e...item=2461316217

do u think that would be a good start?

driving up in the mountains = flooring constantly just about.

So my main concerns are gas mileage, why did it go down so fast,

and whats the more effienct way to make it faster, im a newbie when it comes to cars and i really would like to learn moe about fixing up cars so dont get too technical, just tell me what u guys would do, thanks a thousand!

also 2 of my 4 spark plug chambers fill with oil, i pull the plug wire out and theres all kinds of oil in there, any idea what causes this? does that mess up my preformance"?