Spark plugs shot at 38,000 miles

It sounds like your engine oil may be overfilled as much as 1 quart. The engine oil level should be checked 5 minutes after the car is IG-OFF and parked on level ground.

From your photos it looks like the spark plug tips are totally carbonized. The porcelain insulator at the tip is white when new and should be slightly tan when the plugs are worn. So it was reasonable for the spark plugs to be replaced now.

 

Get some aquarium tubing ($3 at petsmart) that fits in your dipstick hole. Stuff it down in there and suck on it until it almost gets in your mouth. Then place the other end of the tube in a vessel that is lower down than the lowest point the hose is inserted to. i.e. stick a cup on the ground and drain it into that. Wait 2-3 hours depending on how much oil you want out of there.

 

careful not to drink any!

 

Those plugs look fine to me! however they are quite carboned up. Is the engine running rich or is that US fuel?? In my experience those plugs would be almost clean on our fuel.

 

If I were you I would

1. Follow Patrick's instruction (park on level ground, wait at least 5 minutes) to make sure the oil is really overfilled that much.

2. Take photo of the dipstick showing the level of overfilling. (Post here for us to see would be nice too.)

3. Bring car to nearest dealer to have the overfilling witnessed and documented in writing, and excess oil removed.

4. Complain directly to Toyota with all the details (photo of dipstick and receipts from all dealers).

5. Sit back and relax and don't put too much hope on Toyota doing anything about it.