Actually everything on the 2003 and 2004 engines were identical except the throttle body. On a 2003 engine the throttle body has no vacuum lines, but on the 2004 engines the throttle body has 2 vacuum line connections. I talked to somebody in the repair shop at the dealership and they explained that the 2004 engine throttle body had additional vacuum lines that would not make any difference as they did not actually connect to the throttle body simply passed through it like a connector 2003 engine had an additional vacuum connection on a different spot separate from the throttle body it just moved on a 2004 engine to the throttle body I sent him pictures of how I had it hooked up and he said it was right as long as I was using the 2003 throttle body