System Too Lean!!!!!!!!!
Thread Starter
ADOBBS
Joined: Jun 2007
Posts: 2
Likes: 0
System Too Lean!!!!!!!!!
Ok guys,
Like most of you out there probably already know, the "system too lean" codes are a real nightmare. This is where I'm at. I have a 2004 STX Heritage 4.2L V6 and have had this issue for a while now. I've had 3 different mechanics tell me 40 different things and finally found one that I could trust. He checked all over the engine for leaks, checked hoses and connections and cleaned the MAF. I was told that the o2 sensors are doing there function, so it's not those. The SES light came back on after being reset and what I'm what I'm dealing with now is a very noticable sound when the truck is put in reverse. You hear what sounds like a vacumm suking air for a split second while the tranny is engaging. When put into drive, it does it as well but not quite as loud. I'm not sure if this is normal but I don't ever remember hearing it before. Also, when put into drive on a flat grade you can feel a noticable hesitation before it engages. I have also felt some weird things while going downhill on a slight grade on the highway at about 55-65. It seems to be coming from the rear end and you can feel it in the cab like a slight jerking.Could there be a vacumm leak going to the tranny?? I've always taken great care of my Ford trucks and this is my third and last one (hopefully). I'm really stumped at this one. Never did this on the other 2. I did have the tranny worked on at the dealership at about 34,000 under warranty and they did a complete overhaul from what they're telling me. This didn't come about though until about 42,000. Any ideas?????
Like most of you out there probably already know, the "system too lean" codes are a real nightmare. This is where I'm at. I have a 2004 STX Heritage 4.2L V6 and have had this issue for a while now. I've had 3 different mechanics tell me 40 different things and finally found one that I could trust. He checked all over the engine for leaks, checked hoses and connections and cleaned the MAF. I was told that the o2 sensors are doing there function, so it's not those. The SES light came back on after being reset and what I'm what I'm dealing with now is a very noticable sound when the truck is put in reverse. You hear what sounds like a vacumm suking air for a split second while the tranny is engaging. When put into drive, it does it as well but not quite as loud. I'm not sure if this is normal but I don't ever remember hearing it before. Also, when put into drive on a flat grade you can feel a noticable hesitation before it engages. I have also felt some weird things while going downhill on a slight grade on the highway at about 55-65. It seems to be coming from the rear end and you can feel it in the cab like a slight jerking.Could there be a vacumm leak going to the tranny?? I've always taken great care of my Ford trucks and this is my third and last one (hopefully). I'm really stumped at this one. Never did this on the other 2. I did have the tranny worked on at the dealership at about 34,000 under warranty and they did a complete overhaul from what they're telling me. This didn't come about though until about 42,000. Any ideas?????
FULL BLOODED AMERICAN!!!!
Joined: Apr 2007
Posts: 5,179
Likes: 3
From: Jacksonville, Florida
Welcome to the site!! I had a problem like this on my GP after the turbo was installed but mine was running too rich due to the air/fuel ratio because I was getting too much fuel and not enough air. If yours is running too lean then I'm guessing that you're not getting enough fuel??? Try getting it tuned.
Junior Member
Joined: Mar 2009
Posts: 14
Likes: 4
i had the same problem with mine. noticable hesitation. almost like transmission slipping. also the system to lean code turns out it was a spark plug. shot in the dark but from what i got from the dealer these trucks are netorious for fouling spark plugs. oh I have a 04' lariat with 81,000 miles
Senior Member
Joined: Feb 2008
Posts: 4,658
Likes: 28
From: Henderson, NV.
Welcome junior member thorn, this being your first post, you are by far the "King of the Forum". Don't get excited, we tend to pick on newbies. But actually you are correct about the plenium isolator bolts. There are a bunch of non believers here. I know the TSB dates back earlier but I ran across a 2000 4.2 with intake runners in place of the plenium, whats up with that? Which engine installation started using the plenium. Again welcome and watch the dates of the posts, your entry was two years late, just a NEWB. 