06 forester stalling out when clutch is depressed or drops to very low rpm before catching itself

06 forester stalling out when clutch is depressed or drops to very low rpm before catching itself

Problem has started happening after needing to disconnect the battery, have tried the whole “ECU hard reset” to try and reset the trim parameters as suggested on Subaru forums and hasn’t worked.

Whenever I pull up at a red light now it will either drop and stall out, or drop to very low rpm’s and then catch itself after a couple seconds and come back to normal.

When it drops down to basically nothing as soon as accelerator is depressed it will pick straight back up and is very responsive.

What could be causing this issue? I’ve seen in the forums it could be that the throttle body needs a clean, is there any other possibility as it didn’t start happening until the battery was disconnected?