My 2012 Camry 2.5 is a little hard to start lately and has a rough idle for a few seconds when cold. No codes and has about 115k miles on it. Runs and idles fine after the initial 5-10 seconds after start. Temperature this morning was around 50 so not too cold outside. I usually only have to turn the key for about a second and it fires right up so that time is programmed into my head and I just automatically let off the key after a second. Lately that doesn't start the engine and I will have to try again. No issues starting it after it's warmed up. My F150 recently had a rough idle and it was just a dirty idle air control valve, cleaned it and runs great. IDK if the Camry has one of those valves, the throttle body isn't exactly as accessible as my F150 either. Any suggestions?

 

The engine does not have an idle air control valve. The throttle is electric motor operated and the idle is controlled by the computer.

Might try cleaning the throttle body and MAF sensor. Here do an internet search on the engine model for specifics on the task. Use a cleaner stated to be safe for MAF sensors and throttle bodies as in NOT brake cleaner or an aggressive solvent that can damage things..

Note if you disconnect the battery the computer will need to relearn the idle point.

Could also be a failing fuel pump. Perhaps leaking down pressure or not getting up to pressure fast enough. Other issues could be leaking injector, here check for gas smell in the exhaust at cold start.

For safety the pump will only operate when the engine is turning over by the starter motor or running.

The fuel system is not directly monitored as in fuel pressure, flow, etc. The fuel system is monitored indirectly via the A/F sensors for fuel ratio and cam/crank sensors for misfire.