Help diagnosing negative fuel trims/ P2178 / P2188 Rich off/at idle codes

If there is excessive gas in the oil, the most likely cause on these cars is the PCV system is struggling to evacuate the gas vapors OR there is an excessive amount of gas getting in the oil.

 

HPFP seals could be leaking gas into your oil. There is a How To thread here in the forums.

If they are leaking, the gas smell will come a few miles after an oil change.

 

I dont believe it was significant amounts but i am going to change the pcv tomorrow regardless.

 

yeah I just did an oil change like 3 days ago and it does kinda smell like oil. would this affect my fuel trims or act fuel pressure if it was ?

 

Your LTFT's will be very negative, mine at one point dropped to -20. In your WOT logs you will notice a piint where your fuel pressure will drop suddenly and then try to pick up again.

 

my Ltft were never -20 on idle or cruising it’s actually the opposite. It ranges from -0.16 to 20

 

You need to check for some kind of vacuum leak in your car. If its adding that much fuel there is something wrong with your setup.

 

Yeah I’ll do another data log just to be sure but I am running lean on idle (p2187 )so idk.

 

Hi OP did you ever resolve the issue ? I'm having the same issue with my Speed. We check boost and vacuum leak, replaced MAP sensor and O2 sensor, cleaned valves and changed injector seals. I'm still having the same issue rich at idle CEL 2188. Now I have no idea where to look. Any help or suggestions is greatly appreciated.