hey why the hell does this guy seem to think any lumina made in the 1990"s has a distributor cap and rotor. Maybe nobody told him about the technological advances in the automotive indistry but distributors are somewhat like dinosaurs the are almost extinct. Also a vacuum leak will not change your timing, that is controled by your crank shaft positioning sensor, throttle positioning sensor,and icm wich you coil packs (not distributor cap) are connected to. If you try to see if your injectors are plugged good luck you can"t just look at them and see, you have to take them out
and find the right testing equipment wich most shops do not have, but if you want to try give it hell have fun and be prepared to get pissed.