Q: What size connecting rod bearing bearing do I need for a 2004 Toyota matrix xr 1.8L front wheel drive

You should look at the back of the original bearing for the size and part number. If you go to the dealer with your VIN number and engine number you should get the correct one. Unless your engine is a rebuilt engine, a standard size will work. There are different sizes for different rod journal sizes. Measure your journal size using a micrometer to order the correct size. You have three different engine codes possible for your car and only the dealer can get the correct one for you. Measure it to be sure.