I found a Po174 code lean code for drivers side. Drivers side all plugs are carboned up, Pass. side were all good. I feel no miss fire. Shop found a bad Mass air flow sensor and a miss on 2 and 6. Can there be a bad mass air flow sensor with getting a code?

 

MAF sensor should affect all six. So that doesn't fit.
Two and six are on different banks. Doesn't fit clean plugs on one side and dirty on the other.
Exhaust leak at manifold on driver's side seems like a possibility. Showing lean via O2 sensor, PCM adding fuel. Just a guess. Or maybe a slow O2 sensor. Another guess.

 

So it ended up all plugs were really carboned up. Shop diagnostic showed it was a bad maf sensor. Replaced all plugs and wires with oem. Replaced map. Then erased the codes it's running without any codes now after 100 miles. Will this lean code causes it to run rich, does that mean that fuel can get into the oil?

 

Mass Air Flow (MAF) sensor. You said the codes are gone. So the air-fuel ratio should be fine. Not clear if there's still a problem.

Here's your other thread. Let me know if I should stop responding.

https://www.ford-trucks.com/forums/1...ode-po174.html

 

Sorry I meant codes were erased after repair. I thought it would be better to start a new thread with the most updated info. How about replacing the engine oil?

 

I started new trad with updated info.

 

threads merged. No need for two threads on the same issue.

 

ok thanks. Do I need to change the oil too?

 

If it's contaminated yes.

 

Will a lean code cause it to run rich( all plugs were carboned) , which then maybe adds some fuel to the oil. I had the lean codes for 1000 miles.

 

It could have been the MAF sensor (dirty or bad), or a bad O2 sensor signal, or a leaking exhaust system before the O2 sensors, causing the PCM to add too much fuel for the amount of air being drawn in.

Ideally, you'd have a scanner and could watch live data as the engine runs. Without it, you can really only wait and hope.

Old ignition system parts, plugs and wires, could cause misfires which could cause fouling. Worn oil scraper rings also. Maybe it's oil fouling, not fuel fouling. Does it use oil? 209,000 is a lot.

If you don't have codes and the engine runs right I'd just drive it.

 

I brought it to shop, they said on the live data they could see a high fuel trim and that the MAF had some bad readings. Also 2 misfires but it ran fine to me. On my cheap scanner fuel trim look s great know after repairs. They didn't recomend a oil change ( after seeing lean codes) that's what I wounding about for now.

 

Sounds like they probably got the diagnosis right. The fouled plugs don't really make sense but don't really matter, if fuel trims are good and there are no misfires.

Any small amount of fuel in the oil will get extracted by the PCV system. That's what it's for. If the oil is not thinned by fuel it's not really worth messing with.