Thread: bad gas mileage and bad coolent leak?

right now i'm currently getting around 16.5mpg. the stuff thats done to the car is zzp pcm 1.0, ported supercharger and ported lim, k&n cai, 3in zzp catted dp, 180* t-stat, autolight 104 spark plugs, and i'm running a 3.4" pulley. I don't see why i'm getting such bad gas mileage. because before i did the pulley and the pcm i was getting around low 20's. alot of my friend and the people around me say that they got the same or better mpg's after the dropped the pulley size and the tune. along with all that i have coolant spitting up on the left side of the motor around the pullies under the lim...i'm thinking thats the water pump maybe??? what do you guys recomend for increasing mpgs?

what other mods would you suggest i do if i wanna continue to use the 3.4? I might get a 3.5". also i was considering a custom tune. i replaced the coolant elbows for the second time and made sure it wasn't coming from there, along with resealing the lim

so i'm thinking the zzp tuned pcm is the culprit. and possibly conisder goin up a pulley size.

Well I replaced my water pump, and cleaned all the coolant up. Cars running much cooler, and no more leaks. I also replace the pcv valve and the fuel filter and now i'm getting around 22-24mpg's and thats mixed city and highway driving, and i was kinda heavy on the gas. I did order a 3.5" pulley that i will be putting on Saturday or sunday whenever it comes in the mail...and i later plan on doing a custom tune as well. I don't plan on doing much more performance wise for my car so i will probably stick with the 3.5" unless i get headers or something like you guys recommened. Thanks for ur input!