94 S-10 4.3 Z TBI won't start

I have a 1994 S10 4.3 vin Z TBI started missfiring going down the road and then backfiring thtough the throttle body and exhaust then died, would only backfire when trying to start, now nothing it just turns over, have code 43, plenty of gas through throttle body, spark to all plugs, pulled all plugs and cleaned and made sure they were getting spark, good compression, I keep getting conflicting stories on the code 43, some say ESC (which would make sense) others say knock sensor (Parts store said no ESC on truck just knock sensor) I am BAFFLED