can some one help with this
just change oil sending unit check gauge still showing low oil pressure on 1999 GMC Savana 1500
do a manual oil pressure test with gauge. try grounding your sending unit wire at sender if gauge goes all they way up you may have oil pump issues
After you do that test, and you have good pressure on the test gauge, try another (better) sending unit i have seen some aftermarket units that just dont work! Check with GM dealer on sender. May cost more but also worth it!