I am totally baffled and do not know where to start...I initially had this problem in Jan 2010, when I left OK enroute to NC. It died once (in LA) but ran good the rest of the trip. Since I have been in NC, it has ran with little to no problems, but it runs slightly rough, and the check engine light stays on and blinks when I get it running faster than 35 mph... I have replaced the O2 sensors, spark plugs, wires, fuel filter, fuel pump and Mass Airflow Sensor over the past 18 months, in an effort to rid the Tahoe of the check engine light being on and the Lean Bank 1 Code that Advance Auto says it has. I am currently in training and have a few weeks before I have to put it back on the highway to get home. Any suggestions would be greatly appreciated by this US Army Soldier.... Please and thank you!

 

Welcome to the forum and thank you for your service.

Best thing I can think of would be to check the fuel pressure. Others here probably have more ideas