Please help serious problem

Ok guys I have a 1999 GMC Suburban with a 454 wd its the 2500 model. Since Ive had the truck its always had a slight miss. (I bought it used with 66k miles on it in November previous owner cut all exhaust off after last cat.) Well I was driving the other day and it was fine until I parked it I started it up that night and noticed it runnin a little rough not to bad so I didnt think anything about it. The next day I started the truck and it would hardly idle it was running so rich andloading up so bad on the idle that when I did drive t it would smoke and run super bad hardly even able to go. So I changed plugs and wires thinking it was something easy, that did nothing. I got the exhaust welded back on still no change. Took it to a shop they said bad fuel pressure regulator had it changed still nothing. I took it back to the dealership I bught it from today and they said bad TPS so I changed it and still nothing. Ive almost had it with this truck and am considering letting them repo it if I cant figure it out. Ive spent almost 600 dollars and I still cant drive my truck any ideas guys please help me. :banghead:

Ok guys I have a 1999 GMC Suburban with a 454 wd its the 2500 model. Since Ive had the truck its always had a slight miss. (I bought it used with 66k miles on it in November previous owner cut all exhaust off after last cat.) Well I was driving the other day and it was fine until I parked it I started it up that night and noticed it runnin a little rough not to bad so I didnt think anything about it. The next day I started the truck and it would hardly idle it was running so rich andloading up so bad on the idle that when I did drive t it would smoke and run super bad hardly even able to go. So I changed plugs and wires thinking it was something easy, that did nothing. I got the exhaust welded back on still no change. Took it to a shop they said bad fuel pressure regulator had it changed still nothing. I took it back to the dealership I bught it from today and they said bad TPS so I changed it and still nothing. Ive almost had it with this truck and am considering letting them repo it if I cant figure it out. Ive spent almost 600 dollars and I still cant drive my truck any ideas guys please help me. :banghead:

Welcome to AF on first post.
I would be looking for a good repair shop.
Tips on finding one.
Check around Ask around
Word of mouth.
Family friends coworkers neighbors business people and delivery people.
Mailmen and parcel delivery people get around and notice a lot of stuff.
Even a good parts house knows what shops are good and not good.
Chamber of commerce and better business bureau and city hall.
If you find a good referral to a repair shop go look them over and talk to them.
Look for a clean looking busy place with nice people running it.
Ask a few questions and ask about their qualifications and training.
Not all places have trained tech/mechanics.
If they do not find a place that does.
Even all dealers do not have all trained techs/mechanics.

found out what was wrong with my burban I have 0 compression on cylinders 1 and 5. I would just keep working on it but Im just sick of it at this point. To top things off the car lot I bought the truck at is not willing to do anything to make it right. I havent even put 2k miles on it and they are saying it is my fault so, if you live in the Tucson AZ area do not go to a car lot called The Truck Stop on Craycroft and 29th.

Don't give up yet. These are notorious for sticky valves, dump 1 can of SEA FOAM in the oil, dump 2 cans in the gas tank, slowly dump a can down the intake thru the vacuum line that runs to the brake booster while running. You will be amazed at the results.

Jeff