Recently my 01 ranger develped these codes (sys bank 1 and 2 lean). I've reset the PCM (pulled the battery cable) to see if perhaps I just had bad gas that tank but it came back after a couple of days. I'm going to replace the fuel filter as I did let it run down to almost empty once and am thinking some gunk got in the filter and is restricting the fuel flow. I don't have a pressure tester, so I'm looking for other ideas. I'm also going to clean the MAF with some contact cleaner incase that has some stuff on it (although I've read that it's supposed to heat up enough to burn anything off). If anyone has any other ideas please feel free to suggest as I need to get this code cleared quick as my emissions test is due by the 15th of this month. I was actually going to go the next day (it happened on a friday morning on my way to work) to get my emissions tested and then this happened (why, oh why couldn't it have waited another two days??). I don't have any drivability problems, it runs fine, the MPG is about normal (20 city, 22 HWY), so not sure what's going on as I've read when you get these codes you'd normally see some kind of issue (sputtering, etc.). The dang thing runs fine but they won't let it pass the emissions unless it's gone through all the monitors after a reset, and there are no codes displayed. I replaced the plugs about 5,000 miles ago so I'm thinking that's not the issue either. I am in dire need of an oil change as well (I'm over about 10k). Could that cause an issue?

MUCH thanks in advance.

Steve

 

It might be helpful to know which engine is in your ride.

P0171 & P0174 = system lean on both banks. This usually sugests a unmetered intake side vacuum leak, so I'd begin by checking all the vacuum hoses for splits, cracks, loose fit or disconnection.

If all that checks out ok, look to a sticking open PCV valve, or leaks in it's hoses & connections.

If that checks out ok, then look to the intake manafold gasket/s, for loose fastners.

I doubt you have a fuel delivery problem, as you've said you don't have any driveabiliy problems.

If you want to check the fuel presure, it can be done with a scan-tool that'll read PID's. Or maybe you could check a fuel pressure test guage out at your favorite local autoparts store, for a refundable deposit, on their Loan-A-Tool program.

No the MAF sensor doesn't get hot enough to burn off deposits. If you decide to pull & clean it, use a plastic safe, non residual cleaner, like a throttle body spray cleaner, that states it's safe for cleaning MAF sensors & be careful not to damage or contaminate it's wire grid.

If you find the MAF is dirty, you need to look farther up stream & find out why you have a unfiltered air leak past the air filter.

Common causes for a dirty MAF are using & over oiling cotton gauze or foam air filters, poor fitting air filters, improperly buttoned up air boxes, or intake air tubes.

I'd begin with a through vacuum leak inspection first.

Let us know what you find.

 

What's the easiest way to check for vacuum leaks? I had a p0174 before and changed out my K&N filter for a regular one and it never came back so perhaps that's the culprint again, maybe I didn't lock it down tight enough...

 

Which engine do you have????

 

If it's the 4.0L SOHC I would suspect the intake gaskets.

 

4.0-liter SOHC V-6

 

would having bad intake gaskets cause any driving problems? I would think it would run bad or whatever, but it runs normal, no problems at all, no stutters, or stopping or stalling, or anything. Starts right up in the AM.

 

OK, well then add the 4.0L's intake manafold gaskets to your vacuum leak suspect list, as Rockledge has suggeted.

You could rig a propane "sniffer" with a length of rubber tubing & a "sports needle", (you know, the kind used to inflate basket & foot *****), as a precision probe, then start the engine, turn on the propane a little & use the needle to apply propane to suspect areas.

If the engine inhales any through a vacuum leak, the engine rpm will increase.

The propane is senor safe.

Let us know what you find.

 

I'll give it a good once over in the AM, make sure everything is tight and seated properly. I'll pick up a fuel filter and a PCV valve as well. Don't have much money to get it scoped right now so I'll have to make due, thankfully I looked at the plate and I have til the end of the month to figure it out.

 

oddly enough I just filled my propane tank...lol, I'll have to get some tubing, but thanks a ton for the help, if there is a leak I would imagine that would find it.

 

Are you having any "pinging" probems????

The A/F mixture only has to get out of hand enough that the feedback the O2 sensors are giving the computer,are such that it can't compensate the mixture enough to stay within the bounds given it. Then the computer gets unhappy & turns on the I hurt light!!!!!

If the leak is gross, you'd have driveability problems. If it's just enough that the computer can't compensate for, you might not notice.

A check of the O2 sensors switching rate would tattle on things. If you have a scan-tool that'll display the O2 sensors PID's, I'd check that & maybe some things lie the MAF & fuel pressure PID's too.

If you find a intake manafold leak with the sniffer, try retorquing the fastners, in the sequence & to the specified values & see if it'll help. If the gasket has been sucked in, it's replacement time & there are excellent instructions in the Tech Info thread by Rockledge, on how to do it.

 

nope, no pinging problems at all. It rattles if i go over 3k RPM but it's always done that (had a timing chain gear replaced a long time ago that they claimed was the culprit, but it just moved from 2500 RPM to 3k.).

No extra tools on hand except what I can fit in a toolbox (typical stuff a non-mechanic that can do some work on cars might have).

I'll go over it in the morning, check for leaks and such and let you know what I find.

 

Wasn't able to check it out much this morning, had to go to church (wife wouldn't let me out of it...not that I'm complaining), so I'll have to look it over later today. I was reading about that intake manifold problem that Rockledge posted, and a lot of them were saying that they had to replace antifreeze every now and then and got their oil analyzed, etc. My coolant is ok, so I'm hoping it's just something a tad bit loose (although I honestly only lift the hood on that thing just to change the oil every 5k) but I'm sure vibration can loosen things over time. I'll post what I find.

Thanjks again for the help PawPaw and Rockledge.

BTW, if I were able to find a garage that could put it on a scope, would that nail down the problem quicker ? I might be able to barter some computer services with a friend of a friend to have him put it on a scope for me...

 

I bet you were reading about the OHV "pushrod" version of the 4.0L with regard to coolant loss stemming from an intake gasket leak. Your '01 has the SOHC version of the 4.0L, and the SOHCs are not prone to intake gasket coolant leaks. Usually such leaks result only in lean codes on the SOHC.

If you change out the upper intake gaskets, make sure you use OEM brand. Ford re-designed the gaskets several years ago to fit better, and made them thicker, to boot.

Also, when your changing out the PCV valve, inspect the hose assembly for damage. I've seen reports of that causing lean codes, as well.

 

sweet, thanks Rockledge, I'll be doing that a bit later.