When I start up my old truck for the first time every morning it is slow to start. I mean, it takes awhile of turning the key and holding down the gas. I have no idea what it is, the starter itself seems to work just fine, maybe some thing with the fuel. The thing is, after the first time a start it up in the morning, it will start just fine the rest of the day, on the first turn of the key, with no problems. I just want to know what to replace.