10 mpg 93 4.0 4x4

[deerhunter3]

Hey Guys,
New to the forum here and I bought a 93 ranger with a 94 4.0 explorer engine in it also it was all auto and now has lock out hubs and a manual transmission. It has around 150,000 miles on the engine and the truck has a 3 inch body lift with 31's on it. The CEL came on and off and it read that the left and right banks of the 02 sensors were reading rich and lean mixtures. so after replacing countless parts from 2 new 02 sensors, maf sensor, tps, wire set, plugs, and many other parts I am about to give up. The problem is that around cruising rpm range it spits and sputters and sometimes I have a lack of power. I am getting around 10mpg and I am not even getting 150 miles to the tank. I recently put a dual cherry bomb extreme muffler on it thinking it would free up the exhaust system. the only thing left that I can think to do is if the catalytic converter is clogged or plugged. I am running out of ideas. Any help would be appreciated.

 

[swynx]

Check your fpr my truck used to get gpm. Yes it took a quarter tank to go 8 miles for work. My fuel pressure regulator was plugged with black gunk. I now get 20 MPG after replacing 1 02 sensor. Tps. Maf. Iac. Fpr. Cleaning my throttle body. Replacing fuel pump.

And that's after going to bigger 31s with heavier rims

 

[97RangerXLT]

if you have a rich condition from the o2 sensors, you could have a stuck injector. that will not be good for your engine as the fuel will wash the oil off the cylinders and will eventually melt down the catyletic converter.

do check the FPR as mentioned above, and check for vacuum leaks around the intake. easiest way to do that is to spray some carb cleaner around the hoses and gasket areas. if the engine revs a little, you got a vacuum leak in that area. The vacuum leak will give you the lean condition.

AJ

 

[deerhunter3]

Check your fpr my truck used to get gpm. Yes it took a quarter tank to go 8 miles for work. My fuel pressure regulator was plugged with black gunk. I now get 20 MPG after replacing 1 02 sensor. Tps. Maf. Iac. Fpr. Cleaning my throttle body. Replacing fuel pump.

And that's after going to bigger 31s with heavier rims

I actually replaced the fpr but did not do anything with the fuel pump. Can the fuel pump be somewhat working but not fully or is it it works or it doesn't.

 

[deerhunter3]

if you have a rich condition from the o2 sensors, you could have a stuck injector. that will not be good for your engine as the fuel will wash the oil off the cylinders and will eventually melt down the catyletic converter.

do check the FPR as mentioned above, and check for vacuum leaks around the intake. easiest way to do that is to spray some carb cleaner around the hoses and gasket areas. if the engine revs a little, you got a vacuum leak in that area. The vacuum leak will give you the lean condition.

AJ

I tried cleaning the injectors already as well as replacing all the gaskets around the intake and valve covers. now thinking about it I also replaced the right side exhaust manifold gasket because it was leaking and possibly throwing a wrong code to the O2 sensors.

 

[swynx]

People will tell you that the pump is iether working or its not. Even tho it is working doesn't mean its working 100%. When I replaced my pump. The truck quit stalling out. Took half as long to start. Had more go juice. And I got better mileage.

I would replace it.

 

[swynx]

Also shortly after the fuel pump I replaced my coil pack and wires. That helped with gas mileage and go juice to

 

[deerhunter3]

Ok thanks a lot I will look into getting a fuel pump for it then.

 

[deerhunter3]

what would happen if I would knock that cat out and have a free flowing system

 

[94xlt4.0]

knocking the guts out of the cat may hurt the flow because you now have two expnsion chambers that have the exhaust goes into then has to squeeze back down to go through the exhaust pipes. also, its a federal crime to tamper with emission systems(there i said it before everyone else jumped all over you for it).

 

[swynx]

I don't think knocking the cat out would be such a problem on obd1 rigs. When my cat fails ill do the same.

I will say that the stock muffler is very restrictive.

 

[Andy D]

easiest way to check for a clogged cat is to remove the O2 sensor. If the engine runs better then the cat is NG

 

[feellnfroggy]

welcome to the 4.0 club. low gas mileage...lol. However I found a hole in my intake tube between maf and intake, this will F you all up. check for a loose clamp or hole in the tubing. If you recently did any intake changes, start there. maybe go back to stock.

 

[deerhunter3]

welcome to the 4.0 club. low gas mileage...lol. However I found a hole in my intake tube between maf and intake, this will F you all up. check for a loose clamp or hole in the tubing. If you recently did any intake changes, start there. maybe go back to stock.

Yea! Great Idea
I thought I checked that good but I will double check for any stupid mistakes like that!

 

[03RedRanger4x4]

I have a set of 31 inch Mickey Thompson Baja Claw TTC tires mounted on Dick Cepek DC-II rims, are these tires going to kill the gas milage on my truck when I put them on this summer or should it be about the same as my stock tires? I cant see them making that big of a difference on my truck as far as mpg's go.