Pulled the heads off and notice that their appears to be a problem with varying cylinder combustion efficiency. The FI's,ignition voltages,valve seats,compression, and headers are OK but for some oddball reason some cylinders appear to be leaner than others. I am wondering if the fuel rail is causing this lean condition.....it is that, or I'm not getting the same amount of air charge to all cylinders or maybe there is a problem with the exhaust scavenge or even cooling problems between cylinders. GEEEEEZZZZ!!! Any thoughts??
Send out your injectors for a clean and calibration, I found 3 to have a low flow rate and poor spray pattern. Also failing OEM headers can contribute. (I have same variation between cylinders, some leaner than others).
Injectors are perfect and were calibrated...I am looking more closely at the fuel rail set-up....exhaust and air intake may contribute. Using new LM1 O2 sensors and there is still a problem with lean cylinders.
