4.0 crap mileage

[Bunger317]

I assume your 33's are all terrains with aggressive tread, good for off road but not for gas mileage. Unless you do a lot of off roading, I'd replace the tires with smaller diameter all seasons. And keep them inflated properly. If your area is hilly like NH, with 3.73's it will downshift often and that hurts mileage. My 2004 Ranger with 4.10's got better mileage than my 11 with 3.73's. O2 sensors and a fresh set of plugs couldn't hurt anything. Install a vacuum gauge where you can safely keep an eye on it while driving- if the vacuum drops, so does the mileage. Accelerating hard is fun but it's rough on the mpgs.

I figure the tires are my biggest mileage issue. It has new plugs/wires. I'll do 02 sensors one of these days. It'll get re geared soon once I have some spare cash for it. The 33,s are staying lol. I daily drive it to work but also mainly bought it to get me to hunting spots so I'm not ruining my gmc.

 

[Bunger317]

What brand o2 sensor does everyone recommend? I try to put all motorcraft parts on it but am not seeing those available

 

[RonD]

Bosch is what Ford used

 

[19Walt93]

I figure the tires are my biggest mileage issue. It has new plugs/wires. I'll do 02 sensors one of these days. It'll get re geared soon once I have some spare cash for it. The 33,s are staying lol. I daily drive it to work but also mainly bought it to get me to hunting spots so I'm not ruining my gmc.

If you're keeping the 33's going to 4.10's will help power and most likely mileage. If your only regearing for the mileage I wouldn't do it. You can buy an awful lot of gas for the price of a front and rear gear change. More power is always a good reason for me to spend money, though.

 

[Bunger317]

If you're keeping the 33's going to 4.10's will help power and most likely mileage. If your only regearing for the mileage I wouldn't do it. You can buy an awful lot of gas for the price of a front and rear gear change. More power is always a good reason for me to spend money, though.

I'll be doing it for all of the above. Mostly because it's easier on the motor/trans.

 

[sgtsandman]

Take a look at the chart on Tires vs gearing in the tech section. I think 4.56 might be a better match to get the mpg back up and boost your get up and go.

Mine has 3.73s in it with 31” tires and I thought the performance was a little sluggish before the tire upgrade. I plan to go 4.56 but not for mpg (it probably won’t change) but better low end grunt for off road, towing, and hauling. Otherwise, 4.10 would put me back to where I was before I up sized the tires.

 

[Bunger317]

Take a look at the chart on Tires vs gearing in the tech section. I think 4.56 might be a better match to get the mpg back up and boost your get up and go.

Mine has 3.73s in it with 31” tires and I thought the performance was a little sluggish before the tire upgrade. I plan to go 4.56 but not for mpg (it probably won’t change) but better low end grunt for off road, towing, and hauling. Otherwise, 4.10 would put me back to where I was before I up sized the tires.

4.56s are what I would do. Then if it becomes a strictly play truck and I put 35s in it I'll still be close

 

[sgtsandman]

For 35s, you really should have 4.88 or 5.13 (I might have the ratio wrong on that last one). The chart I mentioned will guide you for the best all around performance, best mpg, and best low end performance.

For where I live, best mpg never worked as advertised and over worked the engine. The hills and valleys kill any potential benefit. It’s either middle of the road, or low end for a properly running truck. Where you live may be different.

 

[Bunger317]

Replaced o2 sensors since I got a 172 code. We'll see if that improves mpgs on the next tank.

Also installed a aftermarket trans cooler over the weekend. I'm thinking about bypassing the radiator since the water temp is keeping trans temp close to 200 still.

also want to replace the radiator. What's a good replacement? With air temps over 100° this things running hotter than I'd like even with the ac off. Between the M and A on the gauge. And that's driving easyyyyywith ac off.

 

[Bunger317]

Replaced o2 sensors since I got a 172 code. We'll see if that improves mpgs on the next tank.

Also installed a aftermarket trans cooler over the weekend. I'm thinking about bypassing the radiator since the water temp is keeping trans temp close to 200 still.

also want to replace the radiator. What's a good replacement? With air temps over 100° this things running hotter than I'd like even with the ac off. Between the M and A on the gauge. And that's driving easyyyyywith ac off.

 

[Bunger317]

View attachment 94984

Replaced o2 sensors since I got a 172 code. We'll see if that improves mpgs on the next tank.

Also installed a aftermarket trans cooler over the weekend. I'm thinking about bypassing the radiator since the water temp is keeping trans temp close to 200 still.

also want to replace the radiator. What's a good replacement? With air temps over 100° this things running hotter than I'd like even with the ac off. Between the M and A on the gauge. And that's driving easyyyyywith ac off.

Probably will replace the heater core also.

 

[Bunger317]

Any recommendations on bypassing the radiator trans cooler and what radiator to get?

 

[Bunger317]

This was today driving up a half mile hill with the AC on in 100° heat. Never really came back down till I turned the ac off

 

[sgtsandman]

I think the Explorers or Explorer Sports had that engine and a double row core. That might be something to check out.

As far as the transmission cooler, you could install and auxiliary cooler in the system but you’ll want to check on what the right size cooler would be.

I would do a step at a time though. The double row radiator might be enough to get you where you want instead of shotgunning it.

Another thing to look at is maybe an oil cooler using a sandwich adapter that mounts between the engine and the oil filter. The best systems have a thermostat in the system that only routes the oil through the cooler after the oil gets above a certain temperature. I’m looking at one of these for when I’m towing. Especially if I’m following someone with a lead foot again. The engine was getting hotter than I liked but was not overheating.

 

[Bunger317]

I think the Explorers or Explorer Sports had that engine and a double row core. That might be something to check out.

As far as the transmission cooler, you could install and auxiliary cooler in the system but you’ll want to check on what the right size cooler would be.

I would do a step at a time though. The double row radiator might be enough to get you where you want instead of shotgunning it.

Another thing to look at is maybe an oil cooler using a sandwich adapter that mounts between the engine and the oil filter. The best systems have a thermostat in the system that only routes the oil through the cooler after the oil gets above a certain temperature. I’m looking at one of these for when I’m towing. Especially if I’m following someone with a lead foot again. The engine was getting hotter than I liked but was not overheating.

coolers already in. One thing I do know is to keep these a4ld's cool to make them live. We've desert races a few rangers.

min thinking a new radiator is going to be the fix. I hope.