I just put my "new" engine in about 7,000 mi ago. It started running lean about 4,000 mi ago. I have changed the fuel filter and it is still lean. I do have a small exhaust leak where the header bolts to the pipes on the passenger side. I have a few things in mind I just want to get some more opinions. thanks guys.

 

02 sensor more than likely

 

That exhaust leak in the exhaust manifold area could be messing with pressure and mixtures.

 

Are you getting a lean code on both banks?

 

im not sure, i only took it to auto zone and put it on their piece of @&$^ scanner.

 

Don't trust AutoZone for a diagnosis. They are good for a free code read and not much more. Get the actual Pxxxx code(s) and post them here.

In the meantime, you should fix your exhaust leak to take that variable out of the picture.

 

I found out what was wrong with my ranger, my PVC vavle went bad and my throttle body gasket had a leak and they said my throttle body was messed up. I got a new PCV Valve and put some silicone on the gasket. It is running better I am goin to wait and c if I have to get a new throttle body of not. I hope not. lol.

 

I had that problem on my 01. Had a code for lean on both banks. When I found the issue (the rubber elbow that conects the tube from the PCV to the front of the throttle body) i was sure I would have to order it but when I went to the local ford dealer, they said they replace them all the time and had 26 in stock.

 

hmm so this is pretty common huh? the exact same thing happened to me, had a code for lean on both banks, the rubber elbow was gone and was sucking air bad, i replaced it but i can still hear that something is sucking air somewhere but definetly not the elbow anymore, the code is still there but the engine is running much better i just haven't got a chance to look for that other vacuum leak

 

yea I had one of my buddies clear the code after I did those things. I am just waitin to c if I fixed it all the way or juss partially. we will c here soon. But it runs much, much better.