gerkendave

Hi all, i've got a 2000 silverado with the 5.3 and 4wd, when i bought it about a year ago i was getting about 17-18 with it. Since then i have added new tires, 285's (one size bigger) and to try to compensate for the lost mileage i added custom dual exhaust ( y pipe no muffler out the back w/ fully welded seems) and a FIPK from k&n. i'm still only getting about 15 i was just wondering if anything else could help restore my gas mileage.

ukrkoz

of course, you had your ECM/speedometer correction done for larger tire size, right?
not sure what FIPK is, but go back to stock airbox, install K&N air filter, and drill a whole lot of holes in the box before filter, to let hot air in. i am averaging 17.8 mpg on same powertrain. of course, i have HALO plugs, he-he.

THERE ARE NO POWER MODS THAT WILL INCREASE MPG. most of them will drop it.

bad2006z71

you could do a custom tune by nelson performance or blackbear performance and have the recalibrate you speedo. that will help a little when you are calculating your mpg. also if you drive normally you can see about a 1mpg increase, i did on my 06.

keep the FIPK (cold air intake) its not really hurting or helping you. you could also do a tune up if you havent done one in alot of miles. stick with ac delco parts, more expensive plugs dont really do anything for these motors. change your fuel filter if you havent.

your exhaust might be causing some problems, these trucks need a certain amount of back pressure to operate correctly, but im not real sure on all the mechanics of it.

good luck

gerkendave

thanks guys and no i haven't re calibrated my speedo with the bigger tires. I'm guessing with only one size different its only going to show about .5 mile per gallon different if even that, as my speedo is only off by maybe 1 or 2 mph.
I've thought of doing the nelson tune but for the cost of doing this and the little mpg difference its going to make, it would take a LONG time to see the profit or the worth of doing.
I just got done replacing plugs wires and fuel filter and fuel pressure regulator. I've also cleaned the mass air flow sensor. I then ran a very potent fuel injector cleaner/fuel system cleaner through it that i could only get from my mechanic. After that i replaced the fuel filter again just to make sure it was still clean. If i've missed anything important let me know, the air filter is a FIPK kit from K&N (Fuel injection performance kit) and it is only a couple months old maybe a whole thousand miles on it so i don't think that cleaning the filter will help any.

bad2006z71

Well you dont get a tune for mileage. you get a tune because gm factory tunes suck and you get performance. the Mileage is a benefit.

if they have switched over to winter blend gas then you can kiss at least 1mpg away.

my 6.0 gets 13.5 in the city this past summer, now she's pulling high 11's to low 12's. plus its getting colder.

id get the tune just for the heck of it. id see about putting mufflers back on. could be hurting you some. or run the crap out of it and get a saturn for a DD 30+mpg. thats what i did

good luck.

gerkendave

well i do have a neon (gets bout 28-34) just wanted to see if the ol beast could get back up to her 18 mpg glory days!

bad2006z71

yea i can understand that. i get pissed sometimes riding in a damn saturn when i have a Silverado, but what can you do. LOL