I got a 1995 buick riviera about 3 months ago and it was fine its a nice car then the other day it started chugging and wanting to bog out in reverse but it was doing fine in drive then the next day it died and now it wont even start, i have changed the coil packs but im thinking its a fuel thing it will start if you keep your foot on the gas and reve the whole time........ i am at wit end on what could cause this