10 mpgs???

92exploder4x4 · Sep 10, 2010

I have a 92 explorer xlt 4x4 (recently aquired) and have been getting about 10 mpg's city/hwy. Now, I know these don't get fantastic mileage anyway, but I was at least expecting around 15-16 city/hwy.

Recently I have changed the fuel filter, plugs, wires, and air filter. I do have an exhuast leak at the passenger's side manifold. I tried pulling codes, but I have none. WTF is happening? Anybody got any ideas/tips?

ThatGuy · Sep 10, 2010

I dunno but that does suck. I get 17mpg in my 91 on 36s w/ 5.13 gears.

adsm08 · Sep 10, 2010

Were the plugs gapped correctly?

Does it seem to be running ok?

How is the trans fluid? Do you want to gag if you sniff it?

Do you have a K&N or similar air filter on it?

When was the last time the air filter was changed?

Have you cleaned the MAF lately?

Checked for vac leaks?

Front hubs locked in?

country0001 · Sep 10, 2010

Yeah, what he said, plus the exhaust could be throwing the O2 sensor off

92exploder4x4 · Sep 10, 2010

Plugs gapped right, cleaned the MAF when I did the plugs/wires/filters, no vac leaks, has a paper filter, and not sure if the hubs are locked in, how do I check?

Also, it runs great, drives great, I dunno...

adsm08 · Sep 10, 2010

Well, if you have manual hubs, there is an arrow on the lock and "Free" and "locked" stamped on the outer rim.

If you have auto hubs, go backwards.

Check the MAF. It can go bad without throwing a code on those older ones. You will usually notice a rough running condition with that though.

How old is the O2?

92exploder4x4 · Sep 10, 2010

I have the autohubs, shoulda specified. How long should I have to drive in reverse for the hubs to unlock? As far as I know, the o2's have never been replaced. I cleaned the MAF, with CRC MAF cleaner, and swapped the MAF from my parts truck to see if it made any difference.

The truck idles great, however at times it seems like it drives a little rough, almost like it wants to bog down on me when I give it some pedal, but it's really hard to tell because of the exhaust leak in the manifold (and in the muffler). The truck has 3.73's with stock tires.

adsm08 · Sep 10, 2010

You should only have to go back about a foot to unlock them.

Bad O2 sensors could cause both your poor mileage and the bog-down issue. Country has a point too though. The exhaust leak at the manifold could be screwing with the O2 signal, making the exhaust show lean and telling to computer to give it more fuel.

I'd start there though. Fix your leak and throw a sensor on it. Those thing's don't last forever. They live in a very hostile environment and wear out after 100K or so.

92exploder4x4 · Sep 10, 2010

Cool, I planned on fixing the manifold leak this Sunday, may as well throw a new o2 sensor in there as well. Thanks for the quick replies

adsm08 · Sep 10, 2010

Well, we are here to help.

b2rich · Sep 10, 2010

Fixed my exhaust manifold leak, gave me about 4-5 mpg :icon_surprised:

92exploder4x4 · Sep 10, 2010

b2rich said:
Fixed my exhaust manifold leak, gave me about 4-5 mpg

Sweet, hopefully I can get close to that as well. Only one way to find out

92exploder4x4 · Sep 12, 2010

Well, I put a new manifold gasket on, and it stopped the leak some, but I still hear exhaust leaking by somewhere in the front of the manifold, and I can't figure out where exactly. I also put a new muffler/tailpipe on, it is much quieter now, inside the truck at least. Still have to get an o2 and drop that in, hopefully soon.

92exploder4x4 · Sep 16, 2010

Could bad motor mounts cause a decrease in mileage? I know mine are bad/going bad, m motor shakes like a mofo - even under acceleration.

b2rich · Sep 16, 2010

92exploder4x4 said:
Well, I put a new manifold gasket on, and it stopped the leak some, but I still hear exhaust leaking by somewhere in the front of the manifold, and I can't figure out where exactly. I also put a new muffler/tailpipe on, it is much quieter now, inside the truck at least. Still have to get an o2 and drop that in, hopefully soon.

if your still hearing a leak, more than likely you need to have the exhaust manifold resurfaced.

10 mpgs???

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