2000 alero hesitates changed boots coils sparkplugs modular checked what else can it be need help?

Usually hesitation is caused by lean fuel condition. Most electronic problems will show up in a computer diagnostic scan, but low fuel pressure won't really throw a diaagnostic code, so that's a potential problem. The fuel line will have a test port. Find a fuel pressure gauge and see what kind of pressure you have. You'll need to look in a reference book or ask the dealer what should be the right fuel pressure. If it's low, check your regulator first. If the regulator is ok, check the fuel pump next.