Question about tuneup and gas mileage

[Kilgore Trout]

Finished changing the spark plugs and had pick up a package from ups put about 30miles on my car and my gas gauge barely moved. My old plugs were so black and dirty, They looked like the ones that were born with the car hahah. Anyways the car idles so much better and has better acceleration. Thanks guys!

Great news!

 

[merc123]

What speed do you drive at on the freeway 65mph?

75-80.

 

[vidmaster]

im still trying to figure out why i get 10mpg on avg. I used to get about 250 miles out of a tank with my 3.27's and now I get about 150 w/ 4.10's. Seems really bad. I've been driving it like this for 30k miles now because I have not had a chance in 3 years to bring it somewhere to have tune looked at. Only thing I have not changed yet is my plugs because of all the horror stories with blowouts.