Justin727
New member
I can vouch for that! My slug is the same. Hates to be fuel efficient with any speed above 70mph
gas mileage go-to fixes
- Thread starter mendozer
- Start date
I can vouch for that! My slug is the same. Hates to be fuel efficient with any speed above 70mph
dirteater4
New member
Tires and tire pressure is huge. Changed to 265/75 tires with more aggressive tread and it killed my mileage.
I'll be getting to all these fixes over the coming weeks.
1) I only know of ethanol fuel around Seattle and don't care THAT much to seek out other fuel since that's a once a week errand
2) I have some les schwab tires on there (wildcat) which is...mildly aggressive
3) I try to stay under 70, but not bc of this. I have a crazy wheel wobble and I get nervous above 65 as it moves way too much.
4) I need to keep my hitch
I'll try these and if I can get up to 17 I'll be happy. It seems to really revv up hard when I accelerate, even with a light foot. Not sure if something was somehow modded on it. Either way, I'll look into these things.
thanks!
1) I only know of ethanol fuel around Seattle and don't care THAT much to seek out other fuel since that's a once a week errand
2) I have some les schwab tires on there (wildcat) which is...mildly aggressive
3) I try to stay under 70, but not bc of this. I have a crazy wheel wobble and I get nervous above 65 as it moves way too much.
4) I need to keep my hitch
I'll try these and if I can get up to 17 I'll be happy. It seems to really revv up hard when I accelerate, even with a light foot. Not sure if something was somehow modded on it. Either way, I'll look into these things.
thanks!
I get 22-24 MPG in my 99 5-speed 4x4 in mixed highway/city driving. My commute to work is about 40-50MPH with a few lights.
Driving faster than 65 or so kills my mileage. It'll get 23 at 60-65MPH, 20ish at 70MPH, and 17MPG at 80MPH (which is the limit on some freeways out here).
Given your commute is only ten miles, you're probably running in open loop on your ECU for at least 1/3 of it. This means all the fuel-efficiency-optimizing tricks - like advancing timing based on O2 sensor input - aren't even in play, as the ECU doesn't go into closed loop until the engine warms up.
I've noted the following things will kill my mileage as well:
-- Bad plugs. Runners use a wasted-spark system, which uses up plugs about 2x as quickly (arguably about 3x, since the plugs will erode more quickly as they're firing not only twice as often but twice as fast).
-- Wrong oil. A lot of oil change places will grab whatever's handy and put it in your truck.
-- Tires. Running oversized tires, underpressure tires, or tires with aggressive rolling resistance or tread will be murder on your mielage. Your wheel wobble may be indicative of other tire-related issues.
-- Bad air filter. Swap it out for a non-K&N oiled version if that's what you're running today.
Forget about using better gas; it won't help. The ECU is not smart enough to advance the timing to make use of it.
Driving faster than 65 or so kills my mileage. It'll get 23 at 60-65MPH, 20ish at 70MPH, and 17MPG at 80MPH (which is the limit on some freeways out here).
Given your commute is only ten miles, you're probably running in open loop on your ECU for at least 1/3 of it. This means all the fuel-efficiency-optimizing tricks - like advancing timing based on O2 sensor input - aren't even in play, as the ECU doesn't go into closed loop until the engine warms up.
I've noted the following things will kill my mileage as well:
-- Bad plugs. Runners use a wasted-spark system, which uses up plugs about 2x as quickly (arguably about 3x, since the plugs will erode more quickly as they're firing not only twice as often but twice as fast).
-- Wrong oil. A lot of oil change places will grab whatever's handy and put it in your truck.
-- Tires. Running oversized tires, underpressure tires, or tires with aggressive rolling resistance or tread will be murder on your mielage. Your wheel wobble may be indicative of other tire-related issues.
-- Bad air filter. Swap it out for a non-K&N oiled version if that's what you're running today.
Forget about using better gas; it won't help. The ECU is not smart enough to advance the timing to make use of it.
Bstrom
New member
I gotta agree with this diagnosis - I'm guilty of oversize tires, fast driving and haven't check tire pressure in months. Wonder if changing the 02's will do anything if the EC light is not on yet. Doesn't seem likely.
Drcoffee
Senior Member
What spark plugs are you running. Good doesnt mean correct. You should use double ground double platinum plugs. Single ground plugs wont work well in these engines. I gained 2-3 mpg when I swapped mine out. I prefer the Denso brand.
JudeThaddeus
New member
You gained gas mileage with double platinum? Huh I'll have to try those. I put in regular copper and while those smoothed out the engine, there was no mileage increase. Thank you.
JudeThaddeus
New member
They look like this
These Trucks have the wasted spark system so the ground acts as an electrode on 3 cylinders. Ordinary spark plug get chewed up quickly and the arent as efficient.
I have the dual electrode but not the platinum. I have a few things I have to grab from Amazon, I'm going to grab some and throw them in. Thanks again.
kc01runner
New member
I just took a 200 mile round trip set cruise at 70 got 19mpg flat , I have a 01 with the sport pkg with 180k on it with 265/70 generals .
I read on another thread that ECT can actually increase mpg so I have been using it the whole time. I just drove up to the mountains yesterday to ski and so far there's 205 miles on my tank and I'm jut a hair below half tank. I've never had it that high on the gauge before with this many miles. While there was definitely downhill coasting coming back home, I had to drive up a moderate incline. I just wonder if keeping it on ECT long term affects the tranny is a bad way.
When you're running larger than stock wheels/tires, then maybe. Opinions vary.
ECT just raises the shift points so you hold each gear longer than normal. I don't believe it will harm the transmission.
