Where is the ECM located in this car

This car starts fine and run good for a while then it shut down then it will run and do the same thing. The fuel pum and ignition control module has been replace, I check the spark when you star it but the engine do not run and is very good. I bought an ECM thinking that this intermitent problem is cause by it, but do not know where it is located, does any body knows? Thanks a lot.