poor......well, very poor mpg's. need a skilled opinion

[maroon ranger]

So I'm still clueless as to why I cannot get my ranger to run properly. 1994 4.0l 4x4 manual yada yada. In my last few posts I had stated that I rebuilt the motor. I.E...new heads, all gaskets, and almost every possible sensor under the hood. I did fix a short in my injector wiring and that helped out some. Put me up to an average of 13 mpg, more highway than city. And that's a bump up from the 10 mpg's I started out with.

Anyways long story short everything tests out fine but I have to pull the MAF sensor about every other week to clean it (with proper maf sensor cleaner). After cleaning I get an average 18 mpg for about the first 4 days, then it goes down hill from there. Now why do I have to clean this so often?!?!?!?

Also one more thing. My fuel filler neck is cracked where it mates with the tank and leaks during fuel up. Would this also be a cause to poor fuel milage?

 

[adsm08]

Are you using a K&N MAF fouler?

 

[maroon ranger]

No. Everything under the hood is stock parts.

 

[maroon ranger]

I also didn't mention that I have no sort of egr. Came that way from factory.

 

[RonD]

A leak in the gas tank is a leak in the gas tank, every time you go around a corner gas is coming out.

Next time don't clean the MAF, unhook battery cable for 5 minutes then reconnect, that will reset/reboot PCM
See if mileage improves.
PCM will relearn sensors each time it reboots, so it is in "learning mode" for a few days.
So could be a PCM issue............

 

[maroon ranger]

I will give that a try! And see what happens. But everyone knows what a dirty maf looks like. White fuzzy build up and stuff. Why would mine get so dirty so quick? Just curious. And yes I will have to get a new filler hose soon and get that problem resolved.

 

[adsm08]

Poor system voltage, dirt getting past filter, etc.

 

[RonD]

.......... White fuzzy build up and stuff. Why would mine get so dirty so quick? Just curious. .......

Remove the down feathers from the air cleaner housing.
The salesman was incorrect about the air filter's need to be warm...


Joking aside, I would find the source of that "white fuzzy stuff", get a different air filter for sure, and clean out the air box and it's intake tube.
Also check the air plenum(between MAF and upper intake) for signs of that "white fuzzy stuff".