[pyroom]

Hi guys,

I have a 2004 Saturn Vue 3.5L V6 AWD, and I'm wondering if anyone can help me get some better fuel economy. My dads 2011 f150 gets 20% better fuel economy and it weighs twice as much and has 100 more hp.

I have a custom 3" exhaust all the way back (J35 engines don't have headers), no cats and 2 straight-through mufflers. I also have bored intake with phenolic spacers and a custom 5" silicone short-ram CAI right behind the fog light hole. I'm going to be throwing an under-drive pulley on in about a month.

I was thinking about putting a removable piece of cardboard behind the fog light hole to block the cold air from coming in, and using warm radiator air.

My exhaust is only 5 months old and the tailpipe is BLACK like I'm running rich. I also get the occasional small backfire when I get on it. Would getting a piggyback/standalone ECU make a big difference? They're not cheap.

Would a removable plug like what fart-cans use for silencers help? Would exhaust back-pressure help or make it worse?

I have a scan-gauge that always reads around 20mpg, but at the end of the tank it always ends up being 350km/55l combined 50/50 highway/city regardless of how hard I drive it (rated for 400km a tank city). I also only get 500km straight highway, it's rated for 600km.

Thanks