4.0 sohc feels low on power

[sgtsandman]

How old are your O2 sensors and have you looked at your MAF sensor? O2 sensors wear out over time and if they are the OGs, they are due for a change (mine are due as well). If the Mass Air Flow sensor is dirty, it will effect fuel trims as well.

As mentioned above, the winter fuel will cause a drop in mpg and the longer time it takes to warm up to operating temperature will do the same. Up until the engine reaches a certain temperature, the fuel trim will be running rich to speed up the warm up time.

Check your tires too. Every 10 degrees of temperature change equals 1 psi of tire pressure change, plus tires lose air pressure over time anyway. Even new tires on new rims.

 

[White_4x4Ranger]

How old are your O2 sensors and have you looked at your MAF sensor? O2 sensors wear out over time and if they are the OGs, they are due for a change (mine are due as well). If the Mass Air Flow sensor is dirty, it will effect fuel trims as well.

As mentioned above, the winter fuel will cause a drop in mpg and the longer time it takes to warm up to operating temperature will do the same. Up until the engine reaches a certain temperature, the fuel trim will be running rich to speed up the warm up time.

Check your tires too. Every 10 degrees of temperature change equals 1 psi of tire pressure change, plus tires lose air pressure over time anyway. Even new tires on new rims.

I’m not sure if they have been changed. I was looking through service records I got from the previous( 1st) owners and didn’t see anything. I’m planning on checking the o2 sensors and Maf sensor. One question though, by o2 sensors you mean the ones before and after the catalytic converters or the intake ones?

 

[rusty ol ranger]

I’m not sure if they have been changed. I was looking through service records I got from the previous( 1st) owners and didn’t see anything. I’m planning on checking the o2 sensors and Maf sensor. One question though, by o2 sensors you mean the ones before and after the catalytic converters or the intake ones?

There are no O2's on the intake. Just 1 infront and behind the cat

 

[White_4x4Ranger]

Ok, so all exhaust ones?
Any other intake sensors other than MAF I should check out?
Also, should I check out the injectors?

 

[sgtsandman]

I’m not sure if they have been changed. I was looking through service records I got from the previous( 1st) owners and didn’t see anything. I’m planning on checking the o2 sensors and Maf sensor. One question though, by o2 sensors you mean the ones before and after the catalytic converters or the intake ones?

The one before the cats are more important than the ones after but all play a role. If money is an issue, do the front ones first but don't ignore the back ones.

 

[White_4x4Ranger]

The one before the cats are more important than the ones after but all play a role. If money is an issue, do the front ones first but don't ignore the back ones.

Ok. Can I clean them or is it much better just to replace them

 

[rusty ol ranger]

Ok, so all exhaust ones?
Any other intake sensors other than MAF I should check out?
Also, should I check out the injectors?

Yes all on the exhaust

I wouldnt replace sensors (besides the O2's) unless a check engine is on.

Part quality has been total shit lately

With the injectors i wouldnt look to hard unless its missing

 

[rusty ol ranger]

Ok. Can I clean them or is it much better just to replace them

Replace

 

[sgtsandman]

Ok. Can I clean them or is it much better just to replace them

There is a "chemical charge" in the O2 sensors that wears out over time. There is no way to clean them and recharge that. Replacement is the only solution.

 

[White_4x4Ranger]

Yes all on the exhaust

I wouldnt replace sensors (besides the O2's) unless a check engine is on.

Part quality has been total shit lately

With the injectors i wouldnt look to hard unless its missing

Ok. Just wondering about injectors because I thought: gummed up injector—-> squirt less gas—-> less power. ( my exact thought process by the way lol)

 

[sgtsandman]

Ok. Just wondering about injectors because I thought: gummed up injector—-> squirt less gas—-> less power. ( my exact thought process by the way lol)

If in doubt, get a bottle of fuel system cleaner and dump a bottle in the fuel tank before you fill it up. Run the truck until it's darn near empty for best effect. I prefer Cheveron Techron but everyone that uses these cleaners has their preference. Gumout makes a cleaner as does Seafoam. Which ever you go with, the general procedure is the same. Dump it in before filling. Fill the tank to get it mixed well. Drive it until damn near empty or the fuel light comes on if you have a light and it works.

 

[rusty ol ranger]

Ok. Just wondering about injectors because I thought: gummed up injector—-> squirt less gas—-> less power. ( my exact thought process by the way lol)

Thats solid thinking...but less fuel also equals less "POW!" which will usually create a missfire.

It might not be a bad idea to check fuel pressure...you might have a plugged filter or a dying pump. But to create your problem i would think all 6 injectors would have to be screwed at once

 

[White_4x4Ranger]

Thats solid thinking...but less fuel also equals less "POW!" which will usually create a missfire.

It might not be a bad idea to check fuel pressure...you might have a plugged filter or a dying pump. But to create your problem i would think all 6 injectors would have to be screwed at once

That’s true. I would imagine The chances of all 6 injectors going out at once are pretty slim, unless they were designed with some sort of kill device lol (probably not though)
I just put half a bottle of cleaner in half a tank. I would have waited but i have absolutely no patience and I bought it so I figured why not. I bet just driving it will mix it in well enough. No dash lights going off. Maybe I’ll check the filter if it’s not super difficult to get at.

 

[rusty ol ranger]

That’s true. I would imagine The chances of all 6 injectors going out at once are pretty slim, unless they were designed with some sort of kill device lol (probably not though)
I just put half a bottle of cleaner in half a tank. I would have waited but i have absolutely no patience and I bought it so I figured why not. I bet just driving it will mix it in well enough. No dash lights going off. Maybe I’ll check the filter if it’s not super difficult to get at.

Best thing to do is buy/rent a fuel pressure gauge.

Dump the whole bottle in

 

[White_4x4Ranger]

Best thing to do is buy/rent a fuel pressure gauge.

Dump the whole bottle in

I put the whole bottle in right after I said that lol. I noticed while I was driving it that it would rev freely up to about 3k then suddenly stop pulling. This makes me think that it isn’t getting the fuel and air it needs. Any thoughts