Bank 1 lean code, no CEL.

[fourwheelford]

Truck has seemed a bit off lately, just kinda feeling wierd. I checked it with a code tester and got the p0171, no misfire codes though it was the only one. There hasn't been a CEL as far as I know and im the only one who drives it. Just cleaned the MAF and IAC about two weeks ago new fuel filter within the last 3500 miles, full tune up in the last 7000 miles. I always use chevron 89 octane I didn't know it could throw a code like this without a CEL. The idle seems fine, I just changed the battery terminals so its still adjusting from that but before that it seemed fine no miss or anything like that. My last tank full I ran a bottle of injector cleaner through it.

I erased the code to see if it comes back but aside from the things I listed what could be causing this? I read a post that said a lean condition could burn out a cylinder or melt a plug tip, how likely is that? I can deal with an o2 sensor if thats the case but how do I tell? I hate this truck, if anyone has any ideas I would be glad to hear them, thanks in advance.

 

[modelageek]

Truck has seemed a bit off lately, just kinda feeling wierd. I checked it with a code tester and got the p0171, no misfire codes though it was the only one. There hasn't been a CEL as far as I know and im the only one who drives it. Just cleaned the MAF and IAC about two weeks ago new fuel filter within the last 3500 miles, full tune up in the last 7000 miles. I always use chevron 89 octane I didn't know it could throw a code like this without a CEL. The idle seems fine, I just changed the battery terminals so its still adjusting from that but before that it seemed fine no miss or anything like that. My last tank full I ran a bottle of injector cleaner through it.

I erased the code to see if it comes back but aside from the things I listed what could be causing this? I read a post that said a lean condition could burn out a cylinder or melt a plug tip, how likely is that? I can deal with an o2 sensor if thats the case but how do I tell? I hate this truck, if anyone has any ideas I would be glad to hear them, thanks in advance.

when you put the key to on. can you see the cel light? The code could have been pending and not thrown the light on yet. most times a p0171 is not the O2 sensor( it is the sensor doing its job. Could be a vacuum leak on that head..

 

[fourwheelford]

yeah it lights up with the key on. Is it safe to drive?

 

[modelageek]

I just wanted you to make sure the bulb was not blown. The only time you need to worry about driving is wheb the CEL is flashing. That means you have a lot of misfires that could ruin the Cat

 

[modelageek]

Keep checking the codes. If you don't get a p0174 that means it is something on the passenger side jead. Look for a vacuum leak on the passenger side

 

[dbp]

Well keep in mind that 3.0's have a tendency to have valve problems...higher combustion temps lead to valves going bad (among other things), and lean mixtures cause higher combustion temps.

If it were me, I'd try to get it fixed before it creates a bigger problem. Make sure that all your vacuum lines are in good shape and there are no vacuum leaks. I may even go as far as to change the o2 sensors as far as maintenance goes. I think Ford actually recommends replacing them at a certain mileage, maybe 80k...but I could be wrong. Make sure your MAF is in good shape, maybe clean out the throttle body too.

In either event, if you hear pinging, you're definitely getting that combustion temp too high, so back off, shift down, or whatever you have to do.

 

[fourwheelford]

Well I drove it to work today and back and checked it again and no codes at all. Im not sure what happened but I never had a CEL, I don't think its pinging I used to have a volvo that pinged and Im pretty sure its not. I took the MAF out and cleaned it again and it seemed fine, it did have a strand of cotton on it from the last time I cleaned it two weeks ago so I sprayed the crap out of it anyway and put it back. It has only been a few months since I did the TB and it wasn't that bad at that point.

I have been thinking about doing the o2 sensors but I am sick of putting money into this thing, im gonna pull the plugs on friday when I have the day off and see what they look like, that should tell me if that bank is in fact running lean. I also checked the fuel pressure not to long ago and it was well within range. I will just keep an eye on it to see if it pops back up. Thanks everyone for your replies.

 

[modelageek]

why was there cotton on the maf, you should not clean the wires with a rag just spray the wires. do a tuneup, plugs, wires, pcv, clean maf, iacv, airfilter. rpelace the o2 sensor as maintanance if you want but THEY ARE NOT THE REASON YOU ARE GETTING THE CODE. THE O2 SENSORS ARE WORKING.

 

[fourwheelford]

I use Q-tips to lightly clean the contacts after I spray them. Im only 6000 miles into a fresh tune up and the IAC and MAF were cleaned 2 weeks ago. I checked again today and no code again, maybe just a hiccup in the system. Like I said there was no light at any time and my idle is still normal, stupid truck.

 

[modelageek]

I use Q-tips to lightly clean the contacts after I spray them. Im only 6000 miles into a fresh tune up and the IAC and MAF were cleaned 2 weeks ago. I checked again today and no code again, maybe just a hiccup in the system. Like I said there was no light at any time and my idle is still normal, stupid truck.

As I am sure you know you don't want to touch the maf wires with any thing. just spray it.

 

[fourwheelford]

Was not aware of that, thank you for the info