Hey man, I have the same issue with my celica. I went to Toyota for an inspection and they told me it could be 3 things. 1. piston slap, 2. valve issues, 3. timing chain. They basically told me that my engine was done. I'm getting an engine swap this Friday. I'm thinking of selling my celica after my swap and get myself a Toyota MR-S with a 2zz-ge swap.