I have a 1987 6cy 3.8 Buick LeSabre and the following things have been checked or replaced.
Coil replaced
Ecm replaced
Battery replaced
Alternator replaced
Started tested
Wires replaced
Plugs replaced
timing chain replaced
crankshaft sensor replaced
camshaft sensor replaced
computer replaced and but old back in
fuel injectors tested
fuel filter replaced
And I'm sure there are a few I have forgotten.
The car starting running rough like it was only running 5 cyl. Then one day I drove to work and 3 hours later it wouldn't start, cranked over but wouldn't start. After leaving it jumped to another car for awhile finally got it started but it seem to load up and couldn't keep it started.
Took it to a shop and they said I needed a new coil, alternator and battery.
Picked it up and took it home and as I started driving again it still ran rough, took it back and it has been in the shop ever since (2 1/2 months) they can't find anything wrong.
Now they have to cross the 1 & 5 wires just to get it started and can't keep it started and still runs worse then it did when I took it in.
Getting pretty desperate and this point, this was suppose to be my winter car.....