2012 Ford Fiesta Map Correlation/Lean Bank 1
Smoked the vacuum system via booster line. No leaks visible.
Scoped throttle body, TPS2 had some dropouts in the waveform when raising throttle …RPM), so thought maybe that was the problem. Installed a CoPart-esque re-marketed Throttle Body. Codes persist.
Take a good look at the pcv system. It's known to cause these issues.
It is likely that you have a problem with the oil separator. Intermittently sticking valves (pcv/Oil separator) are hard to reproduce in a bay. I found a similar situation on Alldata Community. Basically, the PCV system sticks open and sucks air when it shouldn't. Looks like this thing is mounted to the block under the manifold. Research this yourself, this is just what I found…
Hello Jordan had this exact car with this problem. AF sensor was shifted. Ended up having to substitute a known good fro another vehicle. Tough problem. Good luck
No sir, air/fuel ratio sensor. Try watching it on a graph from cold start. Mine would shift to a higher voltage value after about 4 minutes. Jut a digital switch up. Since then( several years).have seen same issue on two other Ford platforms. Good luck.
Thank you. Ran out of time and customer wanted ride back. Problem appears gone for now (low-frequency intermittent) so if they come back I'll try this.
Jordan , is the egr functioning correctly ? If it’s not opening when it should the Ecu could view it as excess air entering the inlet manifold . Hope this helps . Dave T…
I suggest you research the codes and perform the appropriate tests following the procedures outlined in the SI. That's what I would do.
I had 1 of these about a year ago. It was the throttle body like yours. I replaced the throttle body. The code came back after a short drive. After checking the mass air flow sensor and checking for excess vacuum in the crankcase and not finding a problem with either, I realized that I hadn’t cleared the PCM memory. I cleared the memory, and the code did not return.
Thank you. Replaced the throttle body, and problem appears to have resolved.. I might have actually done the same as you! Ford always wants to push me through the KOEO stuff and it's such a pain, when there isn't a CEL on I think I've trained myself just to not bother with it!