I had a check engine light come on. Code was B0521H, lean right bank. I checked it with Predator and found the LTFT on the right bank up around 25 and the STFT adding fuel as well.

Left Bank seems OK. I did add headers, removed the pup cats and left all the O2 sensors in place.

Any ideas?

 

Exhaust leak maybe? Check your injectors to make sure you dotn ahve any crap in them. I am having a similar problem on a stock setup and i am trying to narrow down that cause of my pass bank going lean also. I have doen everythign changed back to stock MAF from ported, reverted EGR mod so now only thing that is left for me to check is the injectors.

 

Have you had the intake off?

 

No, intake has never been off.

A tech suggested a header leak but I don't hear any exhaust leaks. I guess an exhaust leak could do this but I am not sure. Would a leak draw air and cause a lean signal to the O2 Sensor?

 

1-exhaust leak near 02 sensor
or
2-bad 02 sensor.

 

One thing I did notice was that both bank LTFT were +. The left bank LTFT were running around +5 to +7 most of the time. STFT was adding and subtracting depending on driving conditions.

Also found a code P0101 , MAF malfunction. Makes me wonder if the MAF was really leaning out right side more than left. Is that possible?