What might cause #3 and #4 to run lean and the rest rich. I assumed my rich condition was related to an exhaust leak but had muffler shop put it on lift and they used their stethascope and didnt find any leaks. I used a temperature gun to read the temps on headers and 3 and 4 were hotter than the rest. I pulled the #1 and #3 plugs and #1 is on the rich side and 3 the lean side. My exhaust smell also indicates rich. Today I will be re-torquing intake and looking over other potential vacuum leaks. I dont have any codes setting and my long term corrections are maxing out especially at idle(according to tuner) I dont really know what im looking at on the data and tuning side(learni g thouth). Any advice or things to consider would be great. Also wonder if I should have tuner add fuel to those two cyllanders as one of my retunes(I just dont know). Thanks

 

Oops I meant to include I am assuming the other are rich too as I did not verify. I plan to check drivers side to verify but I really think its just the lean one per bank. I have also seen#6 and was rich.

 

If you have a data log, upload it to an FTP site. That way we can review it for you.

 

I have the 5 logs I sent to the tuner. I have cold start. Warm start and idle.Normal city driving. Highway driving. And a full throttle pull from low rpm. I did retorque intake(front half was reading about 26ft pounds back was still at spec), didnt have time to confirm plugs. I did have bad vacuum line on the evap I repaired. Ill search out posting on ftp site and try and post the warm start and normal city driving logs. I did look at temps again on the headers and 3 and 4 still high. I didnt log in all the parameters offered but should hopefully have whats needed.

 

i reset the pcm and drove it for a while and then logged it with normal driving and a warm startup and idle as I dont want to waste anyones time given i made gains with vacuum. I also just had it moniter all the pids.

I downloaded some ftp stuff but have no clue what Im doing. Haha its kinda embarassing I dont know what to put for host and how to even get it to were I can upload my files. Tried the help section and a couple other searches and even a different site. Pretty sad because Im sure its so simple. Ill try again when I get time. I did send those logs to the tuner.

 

I'd drive it for a while after resetting the PCM. By clearing the PCM you erased the long term fuel corrections and those are important pieces of data when trying to analyze the data log. It takes a while to insure the engine is operated in all the combinations of MAP and RPM that define the LT correction cells.