1995 Chevy Monte Carlo

My car just stopped on me but before it stopped on me when I wuld start it up it wuld billo out alot of white smoke and when I when I put it in drive and push on the pedal I heard popping sounds like it was back fireing and it took a long time to pick up speed also when I get on the highway and give it alot of gas it wuld rev real loud but I will still be going only 40 mph its kinda like it wnt get out of gear the car just has no power at all I have to ease my way up to 70 I cant just gas it. I took it to a GM dealer and they tld me I needed a cadilit converter and a maz scencer so I got it put on but that dnt wrk so somebody eles looked at it and tld me I need 3 fuel injectors then somebody eles tld me I might need a head gasket