i have an 03 silverado 4.3l v6 having issues starting it has 144k miles...when my truck sits overnight and i start it in the morning to go to work it starts fine but when i try to start it an hour later it cranks over but will not go i have to literally stomp on the gas to get it going.... so ive cleaned the MAF sensor ive cleaned the throtlle body ive changed the air filter ive checked the injectors and no leaks were found. changed the spark plugs, fuel pump is brand new as is the fuel filter im getting correct fuel pressure...so im at a lost here if i could get any help id really appreciate it thanks in advance