I got a 89 Cadillac sedan duvil

Did you look inside the tank to be sure its not rusted as I cannot get it out of my mind that rust or gunk is the issue. Injectors may be clogging up. If anything you need to atleast put some injector cleaner in tank and let it set over night before stating it back up it may help but if there is trash in the tank,lines,new filter, injectors that will not dissolve your going to have to, remove/replace/clean/inspect ect. I would suggest a full tune up, check all other systems for issues. May should check your fuel pressure. If it had gas/ethanol mix fuel put fuel treatment in it that says its for getting water out of the fuel too and/or if your still on the old gas pull tank and drain it and see if its rusty.

I need to where the sinsor is located at on a 1998 Cadillac devil also the speed sincor there are 2 of them I need the one that shows the speed on dash

Weak fuel pump easy and cheap