I've got a 2014 F150 FX4 with the 5.0L V8 and 108k miles. I doubt it has anything to do with this code but I changed the water pump out last weekend. Anyway, I'm getting the P2098 Post Catalyst Fuel Trim System Too Lean Bank 2. I've gotten no other codes and I've cleared it out and it came back. I've read several different sites on the O2 sensors and where they are but if it was faulty I'd get other codes as well right? I also have read this could be an exhaust leak or bad vaccum line. Is there a way to narrow this down? I'm honestly not sure what to look for when checking the lines or for an exhaust leak but assume it's not complicated.

 

I've now tried blowing smoke around the vacuum lines, especially the ones near the water pump, with no luck finding a leak. I've checked the two downstream O2 sensors with a multimeter using ohms and they show to be good, but I'm not sure if measuring ohms across the 2 grounds is a thorough enough check. I had planned on changing the spark plugs anyway so I'll do that this afternoon, I'm assuming that wont help though. I've also considered cleaning the mass airflow sensor but I dont have the right cleaner for it and like the O2 sensors it should throw other codes I'm guessing. Somebody tell me if I'm wrong...I'm just trying what I know and that aint much.

Also, everything I can find only shows one O2 sensor in middle of each cat. Are there not 2 more upstream from them? Because I cant find them and ford parts isnt showing them.

 

Scratch that last sentence. The upstream sensor is called a HEGO sensor if I understand right...

 

Ever find out what the issue was? I have same code, driving me nuts! Any info would be great.

 

I have a 2019 5.0 and am getting this code. Replaced the O2 sensor that corresponded and the code came back.

 

This issue sent me crazy for weeks but I did fix mine. When the light first appeared I scanned and cleared. After a week or so it reappeared so I knew it was an issue. I did the same as you, I replaced my downstream 02 sensor, cleared the code and went on my way. After a week or so light came back.

I Googled the very limited info on this code for this application. I knew it was a lean code on bank 2 so I started with the basics. Checked fuel pressure, it was a little low (I couldn't tell you know the exact specs) but only like a pound or two. So that wasn't a concern.

Next i checked for vacuum leaks by using a smoke machine that i made. I can give you more details and pics on how to make one cheap if you need it.

No vacuum leaks found but I did see a tiny bit of smoke coming out from 2 injectors on bank 2 while rotating the engine. So I ordered 4 injectors. After removing them I did see some carbon build up on O rings and one injector was almost blocked.. so i was psyched i thought for sure this was my problem. Threw in new plugs and injectors, cleared codes and went on my way..

A week later the cel was back on! Now I was very frustrated and overdue on my emission inspection. Being i was frustrated and still had very limited information on how to proceed i actually started to convince myself the normal injector tap was a tiny crack in my exhaust manifold. But before taking on that job I decided to try a smoke test again but I tried it from another port. I removed the hose that goes from fuel tank to evap purge solenoid. Well after pumping in smoke and not finding a leak I started the truck without reconnecting the purge valve hose. I put my finger over the tube coming off purge valve and felt vacuum, immediately I thought "thats not right " removed my finger and heard a little pop, checked it a few times and found the purge valve was intermittently sucking in air.

Damed if that wasn't the problem! I had unmetered air entering the engine. Normally when a purge valve goes bad they just go, that can and will cause your gas tank to actually start to collapse which makes it fairly simple to diagnose. In my case it was a slight inconsistent leak pulling in just enough air to give me a lean code but not enough to collapse my tank.

I orderes the new purge valve but while I waited for it to arrive I disconnected the line and plugged the valve then cleared codes again.. of course i got a cel within a half hour of doing drive cycle but my lean code was gone! I had an evap code obviously since the evap hose was disconnected.

Once I got my new purge valve and installed it my truck was fixed! I was now 4 weeks over due on my state inspection so I needed to perform the drive cycle that ford recommends to get all my systems "ready" once that was done I passed inspection and my light has been off since.

I hope this helps you, I learned allot by fixing this issue but man it had me stumped. Remember there are only so many things that will cause that code, low fuel pressure, vacuum leaks, cracks in exhaust or unmetered air entering the engine. Once i eliminated the obvious I got lucky by finding the purge valve as being faulty. good Luck and please post up what you find!

 

findable!


Mine is a 2012 but I believe its the same valve for yours but check to be sure of fitment.