Drop in RPMs

Hello. Wonder if anyone can help. Have 97 Camry 4 cyl. Car starts and runs great. cold start idle is fine and at spec.. After driving 10 or 15 min, when I stop engine for a few minutes to go to store etc, when I start the engine again after being off 5 or so minutes, engine starts fine but I notice at start RPMs will drop a little to much then in 4 seconds recovers back to normal idle RPM speed. This happens intermittently. Any help appreciated. would like to fix before it progresses to stalling. Car has been well maintained and tuned. Tried fuel injector cleaner, did not help .
Thanks CG

May never be a serious problem. I have seen this before and never solved it, or tried to. Never stalled. Try not worrying about it.

You could check it for codes,but cleaning the EGR valve and/or replacing the O2 sensor are some recommendations.