Gas milage problem please help!!

[Gmann82]

I currently own a 1995 4.0 V6 OHV explorer with about 268,x.. on it. The problem im having is my gas milage is constantly falling and right now im getting about 8MPG which is horrible, because when i first got it at about 250,x.. i got 15-17 which is normal i believe. I just replaced the plugs which needed to be bad and i used high quality, i havent yet seen a change so i also did a routine oil change and used castrol gtx and a fram high milage filter. And still my milage continues to decrease. It also has a newer air filter. Does anyone have any idea what the problem could be?? Please please help. Thanks.

 

[Joe Dirt]

Is your CEL illuminated? If not, are you sure the bulb is good? Looking for codes...

You can try reading to see if any are stored, with my video:

 

[Gmann82]

No it isnt i will check it though

 

[tregare]

I currently own a 1995 4.0 V6 OHV explorer with about 268,x.. on it. The problem im having is my gas milage is constantly falling and right now im getting about 8MPG which is horrible, because when i first got it at about 250,x.. i got 15-17 which is normal i believe. I just replaced the plugs which needed to be bad and i used high quality, i havent yet seen a change so i also did a routine oil change and used castrol gtx and a fram high milage filter. And still my milage continues to decrease. It also has a newer air filter. Does anyone have any idea what the problem could be?? Please please help. Thanks.

First, dump the FRAM filter and get a WIX. the end caps on the FRAM filter elements inside the filter casing are cardboard and tend to let dirty oil leak past eventually. also the anti-drainback features tend to fail and let the oil drain out of the engine back into the pan. the final nail in the fram coffin is the positioning of the bypass valve, where it is in the fram filters allows crud to get washed off the dirty side of the element if the filter is plugged and up into your engine.

something which helped the mileage on my expy and burban (and one of the explorers my family has) was going to a K&N cleanable filter element, better airflow through it and should last the lifetime of your car.

did you replace the plug wires while you were at it? those wear out over time and can cause decreased fuel mileage.

are you getting any oil smoke out the tailpipe? what are your compression readings on cylinders? is there noticeable blow-by in the crankcase?

's all I can think of for now.

 

[my98nnj]

O2 sensors.

 

[Joe Dirt]

I'm thinking O2's as well, just curious if there is a code stored to confirm...

 

[kkjb4x4.0]

Really could be one of a hundred reasons, but as stated check for codes first.The type of spark plug you used is as important as changing them,motocraft are best!Yes a k&n will last the life of your vehicle but will not gain any fuel mileage,in fact if over oiled can reduce your fuel milage and ruin sensors.Bad allignment,sticking brakes,under inflated tires are some reasons for poor economy.You need to really examine your vehicle and rule out causes one by one and not just throw parts at it

 

[Gmann82]

No codes at all and it got ran 4 times. It isnt burning any oil at all, tires are aired up, top of the line plugs, brand new oil change, and air filter. Going to check compression soon but praying that isnt the problem. I dont think its a wire issue because the vehicle isnt missing and is running completely smooth. This isnt just a small thing causing this because i used to get double the gas milage i am getting now or better with the same driving habits

 

[doug625]

always possible you have a fuel leak...just a thought....

 

[Joe Dirt]

What 'top of the line' plugs? Seriously- these things are very, very finicky about plugs...

 

[Gmann82]

Motocraft platinum i beleive is what i got but do different brand of plugs really cut your gas milage in half? I dont think thats my problem...

 

[Joe Dirt]

Yes- we do have severe issues with 'premium' Bosch plugs that can do that along with other drivability issues. You're ok with the Motorcraft Platinums though.

kkjb had a list of good things to check that are not engine related, those would be a good place to start checking...

 

[Gmann82]

Ok thanks

 

[joebroni99]

Hi,

Did this issue ever get resolved? I have a similar issue with my 97 5.0. the gas mileage has dropped down from about 18mpg to around 10 over the last month or so. It doesnt have any cel or stored codes at all. no fuel leak. I havent changed the plugs and wires in about 60k. but could them go that bad that quick and have such an effect

Also i have changed some things in my preventative list in the last month after the mileage dropped.

New radiator(old one had the regular seem crack)
Serpentine belt, idler pulley, belt tensioner pulley, hoses, flushed cooling system, trans flushed, new trans cooler lines.

 

[koda2000]

Hi,

Did this issue ever get resolved? I have a similar issue with my 97 5.0. the gas mileage has dropped down from about 18mpg to around 10 over the last month or so. It doesnt have any cel or stored codes at all. no fuel leak. I havent changed the plugs and wires in about 60k. but could them go that bad that quick and have such an effect

Also i have changed some things in my preventative list in the last month after the mileage dropped.

New radiator(old one had the regular seem crack)
Serpentine belt, idler pulley, belt tensioner pulley, hoses, flushed cooling system, trans flushed, new trans cooler lines.

how many miles on your O2 sensors? stick your finger in the tail pipe and see if it comes out covered with black soot. if so, you're running rich and worn out O2 sensors (before the cats) can cause this. the condition will not necessarily light the CEL. also clean your MAF sensor if you haven't already done it. another sensor that can cause a rich condition, if it goes bad, is the coolant temp sensor. if it thinks the engines cold, it's like driving around with the choke on.

 

[joebroni99]

I assume the O2 sensors are original as I have never changed them and I bought the truck when it had 100k miles on it. Now Im at 165k miles.

Also a side note, the truck does seem kinda sluggish these days...

I changed the air filter in Sept, and I changed the oil last week. I run full synthetic oil in it.

 

[1996BLKBauer]

My 96' has also dropped in fuel economy, went from 15mpgs, to 10mpgs. I really don't understand why, but the truck runs great, no leaks, so I just brushed it off.

I do believe since I have a 1996 Explorer, that possibly one of my manifolds is cracked, or that due to age, and mileage, that the engine is less efficient. In the spring I plan on changing many fluids, replacing the plug wires, and possibly the plugs with some platinum ones, because I used some cheap Autolite ones when I got it because I was unsure the last time they were changed.

 

[Gmann82]

Yes i did resolve the problem! I changed the plugs which didn't make a noticeable difference except maybe a little, then i paid about 80 bucks and replaced my fuel pump regulator it was simple and it took all of maybe 2 minutes! Instantly my milage shot back up to the 15-16 range and has stayed that way ever since! I would definitely unhook yours and see if fuel shoots out, because mine didn't and that is what made me know it was bad. Basically it was pumping in too much fuel is all

 

[Ricardo Hincapie]

Hello to all. I have short time on the forum, but i have the same problem that the original post. I have a 1998 Explorer Sport with 94500 miles on it. The car was 15-16 mpg, but now is making 12.5 or less, i change the thermostat, spark plugs and it cables, the car was tuning up, i change the IAC valve, clean the MAF sensor, put K&N filtter. Additional i change the BCM, because it was bad and was putting 4x4 all time. When i bought this the engine run like i can´t feel it, but now the engine or the car is trembling, and if i put mi nouse on the tail pipe, the gases are out too strong, i can breed almost normally. The car was checked for any leak, and it haven´t.
If some one can help me i really thank, i don´t know what more i can check or change to have the orignial MPG. Thanks and sorry for my english.

 

[drbenz]

To add some more possibilities: the mass air sensor could be going bad, there could be air leaks either on the intake side or exhaust, if on the intake side the mass air sensor won't see the air but the o2 sensors will and the system will enrichen the mixture. If there is a leak on the exhaust side the o2sensors will see the extra air and here we go again with the extra fuel.
To show how easy it is to have a problem, right after I got my truck I did a lot of maintainance that was overdue and when I took a short trip I was really upset to see only 14 tops mpg highway. When I got home and started checking I saw that I had forgotten to tighten the air intake hose clamp. Tightened that up and got up to 21 mpg highway!