what causes a p0352 code on a 2006 toyota avalon?

Question

check engine light flashes on occaison or else stays on continuously. Engine stumbles for a while then runs fine. originally (yesterday), when it first started to occur i thought the transmission was searching for the correct gear while on a 2-hour long freeway drive.

Answer 1

P0352 = Ignition Coil 2 Primary/Secondary Circuit

The code is for the engine ignition coil, you probably have to replaced the ignition coil #2 to fix the problem.