I have a 2005 toyota avalon and had an engine code come up po356 which is cylinder f ing coil,replaced coil and still have same problem,115,000 miles on car and has never been tuned up.

P0352 DTC code which refers to a circuit malfunction in the ignition coil , return and install correct coils and if you cant get back plugs changed take it some where to have it done .

Possible causes
Faulty Ignition Coil 1
Ignition Coil 1 harness is open or shorted
Ignition Coil 1 circuit poor electrical connection
Faulty Engine Control Module (ECM)

What does this mean? When is the code detected? Each ignition circuit is continuously monitored by the Engine Control Module (ECM). The test fails when the ECM does not receive a valid pulse signal from the ignition coil. Possible symptoms Engine Light ON (or Service Engine Soon Warning Light) Lack/Loss of Power Engine may be harder to start Engine hesitation Rough engine idle P0351 TOYOTA Description: The ignition system on the vehicle uses individual ignition coils for each cylinder. The Engine Control Module (ECM) controls each ignition coil operation. The ECM sends a ON/OFF signal to energize the ignition coil to create a spark at the spark plug when a spark is required at the cylinder.

The number 1 cylinder is located at the rear left of the engine, looking from front to back of the vehicle.

Number one cylinder is usually the front driver side of engine. Or looking at the engine from behind front left cylinder.

No !! Take off the grill in front of the windshield u can get to it from there

PO-356 Ignition Coil F
Hopefully #6

HI WILL NEED AN ENGINE CODE TO BE CERTAIN
BUT SHOULD BE 1-2-3-4-5-6
IT SOUNDS DAFT BUT THAT IS FOR ENGINE CODES 5VZ-FE AND 1MZ-FE AND 3VZ-FE
ALL ARE V6 ENGINES WITH THE SAME FIRING ORDER CYLINDER NUMBERS ARE ARRANGED LIKE THIS 1 3 5
2 4 6
FRONT

vehicle is most likely overdue for service or has not had service indicator reset after service.

You have to use a scanner and pull the code out that is causing the check engine light to come on. whatever code/codes you find are probably related to vsc light.
Good luck and keep me posted

Go to AutoZone and ask them to scan the ECU for codes since you have a check light on. They'll do it for free (a dealer usually gets an hour's labor to do this), and they'll give you a listing of the code and its definition. Post those up and then we can diagnose.