2009 Corolla, Engine code P0301
Replaced spark plugs and coils. Cleared code, and the same code came back. Checked ohms reading on fuel injectors, all read 0.13. Swapped #1 spark plug with #2, swapped #1 coil with #3, cleared engine code, P0301 came back. Through all this the engine idle is low. Cleaned throttle air sensor also. What is my next step?