GMC Repair: white smoke,gasoline out of tailpipe also misfiring, power steering pump, ooo miles

Question
i have a 1998 Savannah conversion van 5.7 engine AAA towed it to a shop. at first the mechanic said it was the poppet's fuel injectors sticking he said he has seen this problem before with the gmc blazers.had my van for almost 3 weeks talked to him today, the diagnostic is engine is good but valves leak also plugs shot, and original wires have to be changed.price is still around the same $700*extra for the plugs and wires is this the going rate?i bought the van in 2008 for about$7000,92,ooo miles on it now has 132,000 i have traveled many times to n.j. Virginia beach, from buffalo n.y     i have had minor problems power steering pump, alternator,timing cover,fuel pump, now this is it feasible to keep or should i sell it. disabled!!!!!!!!!!

Answer
I regret to inform you that you are in the process of being RIPPED OFF, quite badly. This guy should not be in business. I will say that usually the janky people in business will double the price ONLY because it is a van and just about anything outside of an oil change can be quite difficult.

 He should have told you this up front. power steering pump, alternator,timing cover,fuel pump have all been replaced and should be good. Why did you need a timing cover? did you need the gear and chain replaced?

IF he has to pull the heads to replace the valve seals. I could see that being 700.00 for that and the plugs/wires. Otherwise demand an explanation.