Jeep Wrangler service Question?

I just got my 2003 Jeep Wrangler SE fixed. It needed like new spark plugs, a tune up, a cleaning job. There was carbon buildup. It needed a new air filter. And also I got an oil change. Stuff like that. The dealership said by doing this work I was able to get better gas mileage. How much better gas mileage are we talking about? I had to spend around $430 to get the Jeep fixed. Was this a good deal? Please help, any advice will be helpful. Full credit to best answer!

I think the standard answer is anywhere from 3-5% . but this is just a guess, each vehicle is different. If you really want better gas mileage try modifing your driving habits, don't jack rabbit start, don't run the engine out in each gear and use a steady throttle position. You can install a vacuum guage and learn to drive by keeping the vacuum gauge (sometimes called an economy gauge) in the green or high vacuum. The gauge will drop to 0 when you accelerate and rise to 17-20 " when at closed throttle. You can spot issues with performance of the engine by reading the gauge too. Your tune-up was about average if they replaced the plug wires, and all the parts recommended. I think these call for tune at 75-100K. Should have had a fuel filter also,

I don't know how many miles you have on your jeep or which engine it has. There is no way to tell how much MPG increase you may recieve (if any). This is all work that the vehicle manufacturer recommends to do at certain milage intervals for preventative maintenence. By performing this work your fuel milage should at least stay the same and the vehicle will continue to run well. If you never did a tune up or removed carbon buildup the vehicle would eventually loose MPG, run rough and lack power. As far as this being a good deal it at least seems average for work described

Routine maintanance is always a good idea.