ok so i have a 97 ls shell, i just finished installing a 99 gsr motor, tranny, and ecu, i have a check engine light but i dont know what codes are thrown yea all i do know is that i cant rev past 5000. it feels almost like 2 step but im pretty sure limp mode is at 3k rpm... someone pleaseeeeeeee help.... i used the 99 gsr harness do i need to run additional wires for vtec? is this why i cant rev past 5k

 

bump, gas gauge also dosent work but its also from a gsr

 

You should really check your ecu codes. Its probably a very simple sensor that is malfunctioning/plugged into the wrong hole. I'm not sure of the harness because your car is obd2a and the harness I believe is obd2b but I could be wrong. Someone will chime in

 

there both obd2a the ecu plugged straight in

 

Yeah but the chassis harness is for a ls not a gsr. You need to run the extra plugs for the vtec. Did you notice that you had extra plugs from the gsr harness that didn't have a place to be plugged into on the ls chassis harness? I did the same swap and had the same issue. Also I changed the cluster and had the same problem. You probably gotta swap the green film on the back of the cluster to make it work right.