I am getting 18 highway and god knows what city for MPG. It's a 97 I6 with 98,000 miles. It idles okay and runs pretty solid. Leaky power steering box. Should I seafoam the engine through the throttle body or use carb cleaner? Also anyway I can improve gas mileage without blowing a hole in my pocket. It's not lifted either it's 100% stock, I use it all the time offroading so don't call me a pavement pounder I also use it to commute to work and would like to get better mpg because I know it should get 23 hwy. please help