code31

hello i have some issues with my 92 sc400 giving me a code 31 and i have read the repair manual and it points to mostly replacing the ecu but before i do that would you guys give some advise on this situation? also when i get on freeway speeds and don't let the throttle stay in one spot the...

Hey guys, I just purchased a 92 ls400 that was sitting for quite a while. Maybe a year and a half. I am going through the whole car and catching up on delinquent maintenance. I recently replaced the fuel filter and cleaned the MAS. After I put everything back together and started it up I took...