Hey guys, looking at curing a lean condition I am seeing in my 05 LSJ Cobalt SS. I noticed my LC1 was bouncing around 17-19.1 while cruising about a week ago. Aside from my excitement from the better fuel economy I figured my MAF was dirty. I cleaned that to no avail. Next, I pulled the wideband and did a free air calibration which didn't help. Under boost it does go to 12.x and during cold starts it acts normal as well. I used HPTuners to command Open Loop while driving, this didn't help. I also did a cylinder balance to see if it could be a bad injector and they were all within a couple percent.

I am stumped on whats next; injectors or 02 sensor. I am throwing no codes to help diagnose this issue. Any pointers would greatly be appreciated.


Info: 2.8 pulley, 42lb injectors, ZZP header and Injen CAI
I've had this setup for over a year with no issues

 

check for a vac leak

 

That is something I hadn't considered, thank you! I'll look into the lines tonight

 

Im having the same issue, The car never goes lean under WOT but when driving around sometimes it will go right to 17 on my wideband (aem) and stay there with no power..then it will come out of it and act normal.

 

Update; checked all hoses and connectors. Sprayed ether around the intake flanges and fittings (with cold motor) no leaks! Any known sensors that can cause a lean condition? Ran a short log w HPTuners scanner and seeing activity on my 02 and MAF....

 

you need to post this in problems and service or In the tuning section

 

Thank you, my bad