jvangel, take the air cleaner out. Look down the engine side of the air intake. That's the MAF in the center. There are some good threads with much detail, do a search on MAF*.

 

97, what size tires did you put on it? We may have found one source with that one, unless you are saying you put tires on after you noticed a mileage decrease. You have the 3.55 axle.

Driving 2 miles is hard on the oil and carbons up the rings. You would do it good to treat the engine with Auto-RX. It won't recover this much mpg, but it will run a lot better. I drive 12 miles each way, and my engine warms up more like 5 miles, and if it gets to single digits it will take the whole 12 miles to warm up fully. Do you get it good and warm durring the week? Do you get a consistant sound out of the exaust or does it sputter once in a while?

 

Hey,

Here is another question. Has ANYTHING changed driving wise? I mean, are you making shorter trips now, or are you in a different location, different altitude?? I know when i go home and drive in town, my truck gets 13 mpg, but here in college station, i get around 7 mpg. Short trips, lots of lights, winter time. Mostly the shorter trips and alot of time idling. It may be there is nothing wrong with the truck. My fiance has a 02 supercrew, and she gets crappy mileage here too, but back home, its ok.

 

Its not the tstat. Thats been changed and its not stuck running open. I've had the problem and now what happens if it is. So thats out.

Tires i did put new ones on but i've notived this when i had the stock 265/70-17's on there. I actually was in the high 10's with mpg, now im in the low 10s with the 285/70's.


The 2 mile trip does suck i know. But the truck is warmed up by the time i get to work. I usually will sit there for awhile just to make sure. I even go for a little drive before going home just to be safe.


Honestly my driving habits have actually gotten better. I dont' go nuts like I used to. I used to keep OD off just so i can listen to my loud *** flowmasters. Now I dont do that anymore. I take it easy as much as possible.

What is that autoRX stuff? How do you use it? My truck runs great its just this mpg problem.


And just to clarify just incase someone was thinkin it. I do no how to do math.

 

what about the weight of my motor oil? I use mobil 1 full synthetic 10w30 all year long.

 

it could be all of the above.

when is the last time you reset the pcm?

have you added anything to the outside of the truck?

start removing your mods one at a time to see if one of them is causing the lower mpg

change fuel brands

short trips less than 20+min are worse on your truck than not changing your oil

with such short trips you prolly already need new 02 sensors because they have been flooded with water over and over again

replace the coolant temp sensor

just because you just replaced something doesn't mean it isn't bad

your rear tires cupped because you didn't rotate them enough

 

what im saying is that you may not have the truck running long enough to average out your mileage. You get much worse mileage when the engine is cold, so even when it gets hot and gets good mileage, if you have good mileage for just a little while, it wont average out very high.

When im at home, the truck takes 10 mins to get hot, then it stays hot for 30-40 mins. When im here, it takes 10 mins to get hot, and then stays hot for 5 or 10 more mins, or 40 mins sitting still idling. Either way, its not long enough and doesnt lend it self to averaging out my mileage.

 

97, I've read here that taking OD off will improve milage, and I have been doing that and it does help, especially when the drive train is cold, and your speed is less than 55.

Auto-Rx is a fatty acid ester that is added to the oil, taking on the properties of the oil. The esters slowly disolve carbon and varnish and the oil carries them away to the filter.

We may be making too big a deal of this two mile trip, but driving that short distance and working 8 hours then driving home takes its toll. There is more blow-by gass on a cold engine which results in more carbon in the ring groves which reduces compression, carbon tracking on the piston, and high levels of soot in the engine oil which leads to sludged oil paths. It's also hard on cats because they don't heat up enough. As I recall they are most efficient at 600*.

I make a lot of 2 mile trips myself because everything is close to my house, but I only stay and hour or less, and often make the trip after the drive home so the engine does not cool all the way.

Driving longer is the solution, but idling is never a good idea. The ARX will increase compression on each cylinder, and ballance the compression across the cylinders making the engine run smoother. It will help, but not 3 mpg worth.

You said you off road, did you ever change the axle fluid, and make sure there is no water in it? The only time I hit 10 mpg I was towing a trailer in 4x4 on a 6* day, and the engine would roar out of stop signs with average acceleration.

 

Change out your DPFE (located at the friont right corner at the throttle body with the green and white hoses on it ) it goes bad and so does the MPG.

 

What is a dpfe sensor? What does it do?

Coolant temp sensor? Im curious to know why?

What about a bad fan clutch? I've had several people tell me that it could be shot since i had a problem with the truck overheating and i have this annoying whining noise coming from the front.

PCM has been reset numerous times. Last time was in mid december when i changed my flows to a single magnaflow.

Why would the o2 sensors be bad cause of the short trips? When I replaced the old ones they actually looked like they were in fairly good shape. Did the same driving last year with short trips in the cold.


all diff/tranny/tcase fluids were changed in feb. '03.


I've been wanting to take out the chip. But beeing its been so cold out i can't handle the tools long enough. Start to loose feeling (bad blood circulation, always cold).

Cleaning the maf last night did help some. I took a nice long drive tonight and was actually able to put on 95 miles on the first 1/4 tank. Used to be 100 with my old 265/70-17 rt/s'(Stock). 95 and i have on my goodyear mt/r's in 285/70-17. So i was pretty impressed.

im going to try and find that auto-rx stuff. Never really heard of it, but its worth a shot. Im also going to try 0w20 full syn mobil oil.

 

well i think the cleaning of hte maf has helped out alot. Mileage is a bit better. Im sure if i had my stock tires still i would be even better.

 

well i thought cleaning the maf helped but it didn't. Mileage still sucks.

Is it possible that the prolonged cold would cause some even crappier winter gas? What is in "winter" gas to cause bad mpg? I know my heavier tires dont' help the situation but i mean i didn't expect a full 3mpg drop.

 

well i thought cleaning the maf helped but it didn't. Mileage still sucks.

Is it possible that the prolonged cold would cause some even crappier winter gas? What is in "winter" gas to cause bad mpg? I know my heavier tires dont' help the situation but i mean i didn't expect a full 3mpg drop.

 

well i thought cleaning the maf helped but it didn't. Mileage still sucks.

Is it possible that the prolonged cold would cause some even crappier winter gas? What is in "winter" gas to cause bad mpg? I know my heavier tires dont' help the situation but i mean i didn't expect a full 3mpg drop.

 

The gasoline companys have a summer and a winter mix for gasoline. The winter mix evidently decreases gas mileage. It has something to do with the size of the molecules in the gasoline I think.