What did Eddie see across the street from Cuca's restaurant?

The answer to your question can be found in chapter 4.
Eddie sees Mr. Stiles's red Toyota parked in front of the Azteca movie theater across the street from Cuca's restaurant.
Accordingly, the truck had been stolen while Eddie was working an errand for Mr. Stiles. When Eddie tells Jose about the red Toyota truck across the street from Cuca's, Jose suggests getting the truck back. Frightened, Eddie balks at the suggestion, leading Jose to accuse him of being afraid. In the end, on Jose's suggestion, Eddie agrees to call Mr. Stiles to let him know that his truck had been found.
Nervously, Eddie goes back into Cuca's restaurant to use the payphone. During his call, Mr. Stiles expresses his grief about Eddie stealing the truck. For his part, Eddie protests the unfair characterization of him as a thief. Eddie next gives Mr. Stiles instructions on how to get to the truck and then hangs up. When Eddie comes out of the restaurant, he sees Jose bent over near the truck and three teenage boys running away from him.
Eddie runs across the street to find that Jose has been stabbed in the shoulder and near his waist. The next morning, Eddie visits Jose in the hospital.