I originaly had a obd1 B16 and i spun a rod bearing last sunday i bought an obd2 ls for 350 bucks i got the motor in and it runs like crap. It is missing and backfiring badly at idle and if i try to rev it slowly. When i rev it fast it doesnt miss a beat. I am running a p75 ecu ls dizzy and the only thing in the car now that is not ls is the tranny and the injectors. The injectors are obd1 gsr. I am throwing two codes 92 wich i know what that one is but i am also throwing code 51. I cannot find this code anywhere. What is it please help thanks alot guys.
AllMotorB

 

Anyone please i really need the help.