Just a little bragging here but normal maintenance my 2004 ZR2 with 76,000 miles I recently picked up needed a little tender loving care like cap rotor plugs and air filter ( K&N ) oh and the alternator was over charging the battery and after taking care of these needs I went from 18.6 mph to 20.6 mph.

 

What did you do to make the alternator stop overcharging the battery? What spark plugs did you use? I have a 2003 2 door that gets only 17.9 mpg on a good day. I would be overjoyed to get 20.6 mpg. Can you tell if the K& N made a difference in increased MPG?

 

Battery over charge was just the alt. The plugs are AC Delco Iridium professional and all the tune up parts and K&N were installed at same time so can't tell ya what the filter added but it fit better in the box than the fram and it's a life time filter so it's a plus for me.

 

When i installed my K&N CAI i got around a 2 mpg boot on the highway but I also did the throttle body mod and sea-foamed the engine.

 

That's good to here sombody breaking 20 mpg. I'm 19.2 before the tune up parts arrive.

 

yea and mine is all stock factory lift and tires need that 3.73 gear ratio and factory height for the mountain roads.

 

I average 20.6 to 22.5 but almost all of my driving is highway.

 

I never got close to 20 mpg on my ZR2 and I bought it brand new in Oct '00. Now a days, I don't worry too much about mileage as it is more for offroad than on. On the plus side I did average 12 mpg pulling my small travel trailer here in the mountains up and over and down the passes!

 

Find that hard to believe

 

So SmokinJoe, the K&N filter was a 'drop in' style/$48.00 list, not a FIPK style/$319.00 list? What was the 'throttle body mod' you referred to?