Idle and bogging problem...
 

2 years ago I ran into a pond of rain about 2 feet deep and flooded my engine. It flooded from the lower intercooler piping not from the intake pipe, so the map(maf) sensor should be fine. After I replaced the head gasket along with the head bolts and got the car running I found the car idleing around 1500 - 2000 rpm. I've tried to adjust tps screw all the way down but no luck, it's still reving at 1500 rpm.

When I get on the gas pedal the car boggs out. But when I slowly step on the gas pedal sometimes it will go up to 4000 rpm then bog out. I also hear a loud hissing noise from the injector side of the engine. I checked all the vacuum lines and none are leaking.

Could this be a tps problem or maybe dirty mainfold? The loud hissing sound seems to be coming from the fuel regulator sitting the the fuel rail by the firewall not sure. Does anyone know if there is a vacuum line behind the engine by the firewall? I do get up to 6psi on the turbo but the engines rpm doesn't rise.
Could it be the idle air control valve? Does the supra have one...

Thanks for the help and sorry for the long post.

Alright just for reference I've fixed the problem. My timing was off, iscv was dirty and broken, tps spring was dead. Lucky I had a spare tps lying around. I cleaned my iscv and adjusted it manually for correct engine idle.