Gas Mileage Issues
Thread Starter
|
New User
Joined: Jul 2003
Posts: 4
Likes: 0
Gas Mileage Issues
Hello everyone! I am new to the board so this is my first posting. I have a 98 Explorer with the 5.0 V8. I had a plug wire go south on me and it cased a terrible miss. I went ahead and changed the plugs and wires and now it runs really smooth. However, my Gas Mileage is in the toilet. I thought that my trip computer was malfunctioning, but my actual gas usage has increased. My inclination is that the 50 or 60 miles I drove with the bad miss caused the O2 sensor to become fouled. But I wanted the opinion of the board before taking action. Thanks in advance!
Junior User
Joined: Jul 2003
Posts: 76
Likes: 0
Gas Mileage Issues
Sounds like a strong possibility. The check engine light has not flashed on you at any time? I had a fouled O2 sensor problem with my '94 Ranger and the check engine light would come on after traveling about 5 hours or so on the interstate. My Ranger has 2 sensors, and I was told to replace them both at the same time. I'm not sure about the 5.0 config.
Even if it's not the cause of the problem, it might be about time to put in a new O2 sensor anyways (depending on your miles). I can only think of a few other possible causes for the bad fuel mileage (dirty air filter, dirty injectors, bad gas, plugged cat. conv.)
Oh yeah...what's your tire pressure at? How's the alignment? Could be robbing some mileage on that end of the equation.
Tim Beck
Even if it's not the cause of the problem, it might be about time to put in a new O2 sensor anyways (depending on your miles). I can only think of a few other possible causes for the bad fuel mileage (dirty air filter, dirty injectors, bad gas, plugged cat. conv.)
Oh yeah...what's your tire pressure at? How's the alignment? Could be robbing some mileage on that end of the equation.
Tim Beck
Thread Starter
|
New User
Joined: Jul 2003
Posts: 4
Likes: 0
Gas Mileage Issues
Thanks for the reply Tim. Yeah, I went through the other possibilites as well. Alignment was done last week and the tire pressures are all good (I usually run 34psi). I replaced the airfilter, oil, trans fuid and filter and differential fluids.
I had the flashing check engine light before I changed the plugs and wires, but not since. What was your gas mileage like when your o2's went? I have lost about 4 miles to the gallon. That doesnt sound like much, but when you are average 19 on the highway and it drops to 14 to 15, that hurts!
Chris
I had the flashing check engine light before I changed the plugs and wires, but not since. What was your gas mileage like when your o2's went? I have lost about 4 miles to the gallon. That doesnt sound like much, but when you are average 19 on the highway and it drops to 14 to 15, that hurts!
Chris
Logistics Pro
Joined: Jan 2001
Posts: 4,123
Likes: 2
From: Fort Smith
Gas Mileage Issues
You have 4 O2 sensors on your 5.0 config. Two on each side. You have 1 O2 on the front side of the cats, and 1 on the back side of the cat on each side. What type of plug wires did you use? The O2 sensors are a strong possibility, but the will kick a CEL almost all the time. Try resetting the PCM and drive it a while to see if there is a CEL that comes up.
You can reset the PCM two ways - 1) By disconnecting the battery for a short time, 2) remove the 12mm bolt on the wiring harness on the PCM and unplug it, count ot 10, then reinstall.
You can reset the PCM two ways - 1) By disconnecting the battery for a short time, 2) remove the 12mm bolt on the wiring harness on the PCM and unplug it, count ot 10, then reinstall.
Thread Starter
|
New User
Joined: Jul 2003
Posts: 4
Likes: 0
Gas Mileage Issues
I did reset the computer by disconnecting the battery. They are Autolite brand wires. They seem to be working fine as the engine is running very smooth. Smoother than the last time I can remember. If the 02's are "lazy", they may not trigger a code, but switch back and forth very slowly between rich and lean. I have access to a scanner, but I haven't tried that yet.
If i end up replacing the 02's could I get away with just replacing the front ones? If I understand correctly, the rear sensors (after the cats) only monitor the after cat ratio for emissions purposes. I do not believe they control Air Fuel Ratio. Is that a correct assumption?
Any more ideas? Any others would be appreciated.
Thanks,
If i end up replacing the 02's could I get away with just replacing the front ones? If I understand correctly, the rear sensors (after the cats) only monitor the after cat ratio for emissions purposes. I do not believe they control Air Fuel Ratio. Is that a correct assumption?
Any more ideas? Any others would be appreciated.
Thanks,
