100000 miles and 15 MPG
 

What can I do to get better mileage? I am changing plugs and wires tommarrow. I heard that if I change the upstream o2s i will get better, but how? I don't have any codes so will that work? Someone also told me to go synthetic because it will get better mileage. I am ordering a volant CAI and GMPP touring exhaust and hoping that will hook me up a little, i would be happy with 18's truck info is in my sig.

My wires are 7 years old with 150k miles on them and I don't plan on changing them anytime soon.

Avalanche's are heavy bitches. If you can find a way to lose some weight that would be a good start. NGK TR 55's are what a lot of people run for plugs. Get a custom tune, that will help a bit.

Stock rims/tires?

yeah ltz 20's

I also have a little miss at idle which i think is plugs and wires but I am not getting a light

Its a truck. What kinda of driving city/hwy mixed? That makes a big difference. If its mostly in city, then don't expect that much! Plus how do you drive it? What speed at the limit or below? How you drive makes the most difference in MPG.

its mixed driving and i average around 60 65 mph daily, 75 or 80 on road trips/hwy

changing upstream o2's is done because as o2 sensors age they tend to get lazy, they may not set a code, but they aren't running at their peak.

So you think they need changing? I would think that would give better gas mileage.

If you get a tune, you can have the O2's deleted.

the rear o2s not the front.

good luck with those o2s i paid 265 for 1 so id rather stay with 15mpg vs 600 fpr just o2s then another 45 for wires or so then another 20-30 in plugs...yeah piss on that.

my truck has almost 50k on it an im modded an still get 20mpg on the interstate an 15.5-17 in city when i allow the stall to locks up

I wish I got 15mpg :D

My fronts are turned off.

But you have to make sure the MAF and VE are dialed in.

goto gmpartsdirect.com and they have the 02's and pretty much everything for these trucks alot cheaper then the dealer. And for some items like the plugs they are cheaper then advanced auto.

well when you DD the truck an break one...yeah i didnt care how much it cost lol.

i still wouldnt change it until you got to 50k (plugs/wires) im all for maintence to make sure the truck stays running smooth. just like greasing my front end every other oil change, and adding an oil additive every other oil change.

your choice on spending the money...

Well mine already has 104xxx miles I just got and I got it cheap. So I did the plugs and wires they were due. Still had the factory ones. I also found out the k&n filter from my 99 silverAdo fit so I put that in. Getting a CAI and exhaust soon. Any thoughts on changing to synthetic fluids? Better mileage?

Yep, those o2's are past their prime in terms of efficiency. I woulda said new o2s (the fronts at least). And plugs for sure, & wires, but u did that. :thumb:
Ya, as iamkeniff said, the rear o2s can be deleted I wouldn't do fronts.
o2s for $265 is crazy, but my iridium AC plugs are $8 ea from Advance. Ouch!
Joshua, 7 yr old wires w/. 150k miles on them and you don't plan on changing them anytime soon? How do they check out? Seems a bit too long.

OP, some have had success w/. a tune for economy to help MPGs. Synthetic extends intervals but since it's all I run for oil, I can't verify a MPG improvement too. Doesn't mean it doesn't tho. My .02.

thanks for the input

Oh ya, is your Avy 4WD? You have an LT1 in her? Like from '93-97 ('92 in Vettes)?

no its 2wd and the dealer code is lt1 I have a 5.3. you know ls, lt, and ltz. mine is an lt1. it came with everything but navi and 4wd.

test new pic

I knew what you meant. but I believe its 1LT

LT1 is an engine 1LT is a package

:nod:

Oh well I didn't know it was 1LT but I definetly know what the LT1 is reverse cooling 5.7

Try slowing down before coming to stop signs and coasting more. Then Keep RPM's below 2000rpm's on takeoff's and drive the speed limit or below. Do this for a couple of tanks and see an increase in MPG. Yes it sucks but it will improve MPG even in a truck.

Also remove all used or need weight form your truck the more the better. This means clean the BS out of the insides. I cleaned my old truck once and it was 200#'s!

If you drive alot like I do get a cheap car to drive. I get 50+ MPG in my TDI diesel. I can fill up with 15gals @$2.78= $41.70. I can drive almost 800 miles on this. Which last two weeks or so. My ole 1999 C1500 "classic" with a Vortec 350 got 15 mpg and cost me $60 bucks a week or more in gas alone!

May or may not help much but changing the fuel filter might be a good idea.

Damn, Guess I dont get the K&N, Oh well, Ill pick Nicks old one up

The stock plugs and wires are SUPPOSED to be 100k mile plugs. Ive never pulled a set of wires off a GEN 3 engine with 100k miles on it and not messed at least one up.

In my 08, I gained a couple MPGs going to Amsoil, I used to argue that synthetic oil was better, but wouldnt in crease MPG. It did in my truck. The tune helped, and the Long tubes, and freer flowing exhaust will also.

For the cost, IMO the synthetic isnt worth it. A good tune is. In fact, a few months ago, I noticed my mileage drop from about 20-22hwy to 15.3-15.7. I figured it was the dusty parking lot I was parking in. During warm weather I could hear a slight pinging, but kept driving. When I bought my HPtuners cable from the friend that had it, I had him email me the tune "matts 93 oct tune" Went back to 93 octane, and Im now getting about 3mpg better. If I slow down from 80-85, to about 75-78, Ill get closer to 20. I also have heave 20" rims that hurt.

As far as cost effective ways to increase the performance and MPG, Id go with LT's, ORY, freer flowing muffler (I like Magnaflow) and a tune

How much does yours weigh? So I am going to see you Tuesday or Wednesday right?

The plugs might supposed to be good to 100K. I assure you, they're not. :nono: I found out from personal experience & from thru someone else that handles IIRC, warranty work @ GM & said they're just not lastin that long in their (GM's) findings. 75-78MPH isn't doin any favors either. To go from 20-22MPG down to 15's as a percentage is huge. I'd flip out. Ever change o2's?

Tune & driving habits seems to be biggest factors. Then prolly maintenance. ;)

Its fat!! Not sure how much it weight

I changed ont O2 cause I broke it, the truck just turned 40K earlier this week, Im not spending $500 every couple of years changing O2's. The 20-22MPG down to 15 was due to using low octane gas with a high octane tune. Under 80-85 it wasnt that big of a difference. I dont worry much about mileage, but I do watch it. Of all the vehicles Ive owned which has been a lot, every one of them has always gone from full to empty every tank, so......gotta have gas.
I agree about the plugs, 100k mile plugs or no, Im gonna change them before that. That being said, I usually replace with the NGK TR55's, NOT the TR55i(x)? I dont usually replace with irridium. I feel more comfortable changing them ever 20K miles with $20 worth of plugs as opposed to $65 every 100k miles

Wow! Only 40k on a 2000 model, that's awesome. No, I'm not sayin spend $500 on o2's every couple yrs. That put a person in the poor house just doin o2's alone. For some reason I thought u had over 100k. Gotcha on the octane tune. If changin o2's often I'd change that fronts if I had to pick instead of all 4 if on a budget. I was sayin 100k on stock platinum or iridium, whatever '02 Silvy came stock just won't cut it.

You do know that $20 every 20k is more for plugs than iridiums @ 100k. :lol: 35% more. :P
Long as it works for you, & like u said, that makes u more comfortable, just thought I point out. :)

Doh! My bad. I was talking about my 08. My 00 had more than 100k, but I changed the engine pretty regularly :jest:
I know the iridiums at $8ea changed every 100k is cheaper than the non Iridiums at $2.50 changed every 20k but in a modded engine, personally I believe more maitenance is required. If nothing else, it gets me under the hood where I may notice an issue that would otherwise go un noticed
besides that, I do agree that while GM says the plugs are good for 100k, it's hard for me to believe they don't have more spark degridation over 100k than the non iridiums have at 20k, hell I could very well be wrong. On my 08, th plugs will be pulled at 100k and replaced with iridiums, on my toy, it'll get the standard non iridiums and changed every 20k or so

on my toy, it'll get the standard non iridiums and changed every 20k or so[/QUOTE]

:metoo::burnout: