Running lean in bank 1

[Gecko]

So my RPM's have been acting weird that last week. When I go to slow down to a stop they will drop to almost 300 and then bounce back up and come to an idle. My Idle is usually at 750 but recently has been anywhere from 600-750. I thought maybe it was a trans issue, and I read on another forum that if you put it in neutral and it doesn't do the drop that it is a trans problem. But I found out that was only if you were stalling and I haven't stalled yet.

Today I hooked up my tuner to my truck to check my CEL and see if there were any codes I didn't know about (I currently have the 2 codes for having no cats, I just haven't finished my custom tuning yet so they will be gone soon). I got the 2 codes I'm used to seeing but I also had a third. I don't remember it off the top of my head right now (I'll get it again later) but it said I was running lean in bank 1.

I haven't had this issue in the last couple months while having the CEL on so I'm wondering if maybe because it's so damn cold here that it may have something to do with some fuel line pressure. This is only a guess though.

When I did my last data logging everything was good and my tuner said everything looked great.

Anyone have any ideas?

Edit: the code is P2096 Post Catalyst Fuel Trim Too Lean Bank 1

 

[Gecko]

From what I'm reading if I replace my o2 sensors I should get rid of this code. I guess it's possible I ruined my o2 sensors running w/o cats. Can anyone confirm this? And would this get rid of my RPM problem?

 

[MegaMouseGW]

The rpm problem may be normal. If you have an automatic, until the convertor uncouples it will make the rpms drop a lot. With a manual the drop is not as bad because most people will disengage the clutch even before it gets to normal idle. My daughters truck will drop rpm's whenever coming to a stop. Always has. She has the 4.7l with an automatic in it (was my truck until it became hers on her 16th birthday). Even with My V10 the idle drops a bit when coming to a stop. I really haven't watched it too see how far it drops but I can hear it.
If you are not getting any codes then do not worry about it unless your truck starts to stall.

 

[CKH]

If you are getting the too lean on bank 1 code, you may have a leak somewhere in the system before the 02 sensors. Where I would start is by checking for exhaust leaks at the header to head and header to y pipe or whatever your setup is, check if there are leaks at the front o2 sensor locations as well. Then I would move on to replacing the sensors. If you aren't running cats, your rear o2's really aren't necessary, they just tell the computer if your cats are doing their job. Your front o2's are the ones that would throw the lean code and are possibly causing your issue.

I just saw cutouts in your sig, check those for leaks as well, depending on where they are located could be causing the lean code.

 

[KGBIGCOUNTRY]

If the cut outs are close enough to the up streams it will throw the code and the PCM will try to compensate. Your o2s are not damaged from running with out cats unless when you were doing the exhaust you beat on them or damaged a wire by cutting or laying against the header. I havent had cats in years and the front still work great, the rears are "turned off" in the CMR.

 

[Gecko]

The rpm problem may be normal. If you have an automatic, until the convertor uncouples it will make the rpms drop a lot. With a manual the drop is not as bad because most people will disengage the clutch even before it gets to normal idle. My daughters truck will drop rpm's whenever coming to a stop. Always has. She has the 4.7l with an automatic in it (was my truck until it became hers on her 16th birthday). Even with My V10 the idle drops a bit when coming to a stop. I really haven't watched it too see how far it drops but I can hear it.
If you are not getting any codes then do not worry about it unless your truck starts to stall.

I hope it is normal, but it didn't start happening till about a week ago. Thats the only reason it worries me.

If you are getting the too lean on bank 1 code, you may have a leak somewhere in the system before the 02 sensors. Where I would start is by checking for exhaust leaks at the header to head and header to y pipe or whatever your setup is, check if there are leaks at the front o2 sensor locations as well. Then I would move on to replacing the sensors. If you aren't running cats, your rear o2's really aren't necessary, they just tell the computer if your cats are doing their job. Your front o2's are the ones that would throw the lean code and are possibly causing your issue.

I just saw cutouts in your sig, check those for leaks as well, depending on where they are located could be causing the lean code.

I just went out and checked my exhaust and I can't see any visible cracks or such that would cause this to happen. I drive around half the time with my cutouts open and I've never thrown this code before. I'll listen for any leaks when I start her up later today and see if I hear anything.

I've been waiting to throw on my revised tune till I do inspection as I figure I can clear the codes for the rear o2's but still show that they are on and if they need to plug up the OBDII port they will see no problems. The revised tune has the rear o2's off. I'm thinking I may have to throw the new tune on to see if that maybe fixes the problem.

 

[KGBIGCOUNTRY]

The rear o2's do not effect running, they just say if the cats are working if you had them. The upstream o2's are the ones that effect running.

 

[Gecko]

The rear o2's do not effect running, they just say if the cats are working if you had them. The upstream o2's are the ones that effect running.

True lol I know that too. I guess I'm just trying to fix the problem by any means I can think of.

 

[KGBIGCOUNTRY]

Just didnt want you buying sensors for no reason.

 

[Gecko]

So while driving home tonight from work I noticed that whenever the RPMs drop as im slowing down to a stop that the gauge cluster also dims and then lights back up. My battery is fairly new so I don't think its that. Could I maybe just have a faulty wire somewhere causing this whole problem?

A little story that may or may not be related as well. I went to see a movie with a buddy of mine last week and when we went to leave I started up my truck. My radio didnt turn on, which happens sometimes when it is 10 degrees outside (I have a faulty wire somewhere there too). Anyways I shut the truck off right away so that I could then get the radio to work. Well when I tried to turn the truck back on she wouldn't start. All my electronics worked and my lights and everything was strong I just couldn't get the truck to start. We sat there in the cold trying every few min for about 10 min before I decided to grab my tools and unhook my battery and just see if that would work. I got everything hooked back up and tried again, this time it didn't start right away, but i gave it a little gas and then she came alive. I haven't had her die like that since but maybe this caused the problem/ is related to it?

 

[CKH]

The gauge cluster and headlights would dim if the rpms drop too low because the alternator wouldn't be putting out enough juice.

Sounds like your battery may be on it's way out. I had a somewhat similar issue in my Charger where the battery went bad. It would power accessories and headlights because it was putting out enough volts but it didn't have the amps to turn the engine over. You may wan't to have your alternator and battery checked and go through and make sure all your ground wires are in good shape.

I don't believe your electrical issues would be causing the lean code. Checking for exhaust leaks can't be done by visual inspection alone. You have to listen closely to the exhaust, which is difficult when you have an aftermarket setup that is much louder than stock. Also, cupping your hand near the welds and connections, not actually touching the pipes, just close enough to feel for a leak, is necessary sometimes. Of course, it should be done within a minute of first startup so you don't end up burning the **** out yourself.

 

[Gecko]

The gauge cluster and headlights would dim if the rpms drop too low because the alternator wouldn't be putting out enough juice.

Sounds like your battery may be on it's way out. I had a somewhat similar issue in my Charger where the battery went bad. It would power accessories and headlights because it was putting out enough volts but it didn't have the amps to turn the engine over. You may wan't to have your alternator and battery checked and go through and make sure all your ground wires are in good shape.

I don't believe your electrical issues would be causing the lean code. Checking for exhaust leaks can't be done by visual inspection alone. You have to listen closely to the exhaust, which is difficult when you have an aftermarket setup that is much louder than stock. Also, cupping your hand near the welds and connections, not actually touching the pipes, just close enough to feel for a leak, is necessary sometimes. Of course, it should be done within a minute of first startup so you don't end up burning the **** out yourself.

Could the battery go bad after only a couple months? I changed it out this fall when previous one died. I'll have both the battery and the alternator checked to see if maybe they have anything to do with it.

As for the lean code, my tuner didn't say he saw anything when I sent in my last data log, though I don't have an A/F gauge hooked up yet to really determine that. I've looked up a more about the code and it seems I could have a fuel pump not pumping with enough pressure or maybe a corroded fuel line. Anyway I can check these myself? I guess it is possible to have corroded lines with the winter we have had here and all the salt and whatnot. Just throwing out other options to see what you guys think?