so I think its the o2 sensors...but they say it might be the fuel filter...what should I do??

 

I would go with the o2 sensors. I would think the fuel filter would make both banks lean.

 

just replace every sensor.. thats the way your supposed to diagnose a problem


JOSH

 

I'm like Josh, that's what I'd do.

 

Don't do that...it's unecessary and costly.

You can try a few things...

Try replacing the fuel filter. That is cheap, easy, and you need to do it every 18-ish months / couple years. It's good for fuel economy, blah blah, etc... $$$ = $5 = NEED IT ANYWAY

Check your spark plugs. Make sure they are all gapped to .056" apart. Replace spark plugs if regapped and if plugs look good with no deposits or discoloration. $$$ = FREE

Thirdly, you got the "Bank 1 & 2 = Lean" code with a Check Engine Light...get a small bottle of propane, start your truck, and let the gas leak out of the bottle. Put the gas close to the intake manifold of your engine, right where your 1st & 2nd piston are (if you don't have a Haynes manual, borrow one, buy one (ur gonna use it later), or ask someone on here where it is. I believe it is the front right 2 on the truck (looking forward from the inside the cab). If you truck begins to IDLE SMOOTHER...you have a gasket leak. Not critical, but you will need to eventually need to replace the upper valve cover gasket.

$$$ = Cheap insurance to correctly diagnose the problem using about $6-7 dollars worth of propane. It is cheaper than paying $50 / O2 sensor...which x 3 = $150 + TAX. The valve cover gaskets costs $10 plus a couple dollars for RTV sealant...



TRUST ME...do not replace all O2 sensors for craps and giggles. Your stock sensors are good for at least 160,xxx - 200,xxx miles if not more.

Valve cover gaskets are a big time problem for rangers...


From 1995-2000 with the 60* OHV blocks, Ford used paper gaskets!

Pete

 

The fuel filter would starve the entire engine. Not just 2 single banks...

Another option is to use the carbon despoit remover (Fuel Injector Cleaner). That is if you FI are dirty, but if you replace a fuel filter this will change and slightly improve. You could do that as well.

 

Wow so it could be a gasket leak....Idk if its that seriose...it runs smooth as hell.....and its been getting great mileage but down on power...i think its a combination of fuel filter and o2 sensor....where are the o2 sensors on the 03 4.0

 

i was joking about just replacing sensors, but it seems that is the trend on these forums. people just start replacing stuff due to others gueses, which alot of the time goes no where except cosing money. now if you had an 02 sensor open circuit code or something i would say thwo in an 02 sensor (just because me wasting my time to test the wires is not worht it when most of the time is the sensor) but when you just have a bank "x" code lean or ritch its usually solved predy ez.

i dont/havent used propane but it will work, i prefer using brake cleaner due to the fact i can pin point exsactly where i want to with the litle straw attachment. but start by listening for a sucking sound itl be like a hiss. try to isolate the area the hiss is comming from and then use the brake cleaner/propane/carb clleaner/ ex and spray in the area till the idle raises OR runs ruff or runs better (basically untill it changes) now if no external leaks (meaning from manifold directly to outside air) are found that means you mostlikly have a crankcase leak ( PCV system) try pinching off any and all PCV hoses from the intake systematically untill the idle changes gets better and so on..

good luck, JOSH

 

Yup, that's another method. Sometimes it can get a lil messy, but still the same concept.

My truck ran smooth as well, and it idled well and I thought the same thing you are thinking now. I had a slight power loss, but not significant to really be a big deal. I depends, but Ford DID use paper gaskets for a long time. It is worth testing and seeing if that is a problem after you clean your fuel system...

And yea, I thought you were serious. A lot of people on here really don't know how to diagnose problems, and just start replacing right & left. *shrug*

What have you done, thus far?

 

replaced 1 o2 sensor...and im waiting for now...it just got some fuel system cleaner so its not that....the o2 looked pretty nasty so idk

 

ok so its still broke and my inspection is overdue

 

The 4.0L only has two banks, left and right, so a lean condiion on both banks means essentially that the "entire engine" is being affected.

Replace the fuel filter. Clean the MAF sensor. Check for vacuum leaks.

 

There is a noticable power loss Im not sure whats going on probably thinking of trading it in now

 

So i was checking all the hoses and the one between the maf and the throttle body appeared to be loose....unplugged it and truck started running extremely ****ty (worse than it had been) plugged it back up and pulled the intake off...cleaned the throttlebody and reset the computer.....gonna drive it around for awhile and see if thats the problem

 

Cool. BTW, the PCV hose assembly is also prone to air leakage on the SOHC...

 

where is that at....I dont have a manuel...

 

https://www.ranger-forums.com/forum2...ad.php?t=45387

https://www.ranger-forums.com/forum2...ad.php?t=46971

 

For some reason, I was thinking "piston."

 

And did you clean the MAF & IAC ? The MAF could be at fault & dirty...quick to try out...along with the IAC...unbolt, spray, spray again, replace.

 

yeah I got the codes checked at autozone and they said maf....Im going to a shop near me to get the codes read with a better snap on scan tool

 

Well, you can very well clean the MAF with brake cleaner before going to get another scan. Doing this will knock out one other potential problem...pretty easy to do...

 

cleaned it last night...gonna reset the computer now....this is starting to bug me now...

 

update: put it in the shop...when you let it idle it idles erattic.....and it stalled out twice today

 

Has the PCV valve/hose assembly been checked yet?

Has the fuel pressure been checked? Fuel filter been changed?

After that, I would also be considering leaky intake gaskets.

 

Update?