had a similar on my 89
turned out to be a corroded connection at the starter. rather than deal with the fusible links and the tube behind the manifold, i ran a new wire directly from the positive terminal on the battery, beside the fender and across the firwall straight to the juncton block. use a #10 red wire and put an inline fuse near the junction block. the places gm would think to put a fusible link. since i did this my rear window seems to work faster???? low voltage before maybe???
real user name
restore 89
not real good on the comp, and could not log in at home with different email address, because i forgot my password
good luck
chris