camaro died, o2 sensor code, but didnt fixx it
 

i sold my buddy a 98 z28 LS1 M6 car......95000 miles......stock other than 373s.....he was driving on the highway, then came the ses light......a few seconds later he said it felt like he was driving on 4 cylinders.....about a mile later he got off the highway, and it sputtered then died.....got home, scanned it, and got 3 codes.....1 was bank one upstream communication loss, the 2nd one was a bank 2 upstream code, and the 3rd was the same code, bank 2 upstream no communication.......so my buddy removed the downstreams and moved them up to the front....all were acdelcos......again, when he starts the car it barely starts and sputters than dies instantly.....see if it was o2 sensors tho, shouldnt the maf tables kick in if both sensors werent working and the car be drveable? however, forgot to mention the car has been street tuned using hptuners........he ordered new densos or bosches and we will see if that works, but it doesnt seem like it will......any help appreciated?

sry, forgot to ask him exactly what the codes were.

and the tune was done over a year ago so shouldnt be a factor, and the MAF is clean

swap out the maf from another car for a cheap test

Any luck?