Hi, my car has been diagnosed with multiple codes from my engine light being on: P0740 saying"torque converter clutch solenoid circuit/open" the other two codes are P1456, P0420, and the rest are miss fires. I assume its from using unleaded or 87 octane gas a while ago, I had a couple spark pads replaced after that happened. Is it possible to fix my Acura without replacing the transmission, or is it just not worth it?

 

P0740 is a sure sign for us with the 5 speed that the trans is dead..
But since you have a 99 that means you have the more reliable 4 speed, Might wanna check that solenoid.

How is your ATF color like? how many miles does it have?