96 burban needs your help (long)

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by Stand On It, Oct 15, 2007.

  1. Stand On It

    Stand On It New Member

    when you press the gas peddle the truck just woln't go sometimes. It's almost like there is a sweet spot and you have to get into that spot to accelerate. Turning tha AC on makes it 10 times worse.

    A Little History:
    I bought the burban used almost 3 years ago. we had the dealership change the fuel pump (after trying 2 pumps from advanced that didn't work). Incidentally, the gas gauge hasn't worked since, but I just use my trip odometer to keep from running out, so NBD. We have also had to change the water pump, clutch fan, belt, tensioner pully, ac compressor (only the pully was bad but we knew the compressor had a tiny leak according to the mechanic that serviced the ac the summer before). All pretty normal stuff I'd think in the course of 3 years for a truck that now has 200k miles on it.

    Recent History:
    Back in Aug on a trip from Myrtle Beach SC to Augusta GA we started having prefomance problems. Before that the burban took the hills between Columbia and Augusta like a champ, no downshifting, no loss of speed, with or without either AC or CC. The truck started lugging down in the hills. We were losing sometimes 20 mph. Definitly something wrong. We took it to Advanced Auto and thier code showed a multiple misfire something. My husband changed the distributer cap and rotar button (we had installed new plugs only a month before). Same problem on the way home, no power. We took it to the dealership and they said it needed a catalytic convertor, new plugs and wires, and a fuel injection cleaning. I let that sleeping dog lie, because I didn't and still don't have the money for all of that work. My husband changed the spark plug wires and we left it at that for a while.

    Three weeks ago we made another trip to GA and it lugged down to about 30mph so my husband pulled over, totally frustrated. I had him disconect the battery for a few minits when we reconnected the SES light went out and we were able to get down there and back, I drove, without it lugging down that badly agian.

    Two weeks ago knowing we had to go to GA agian (his family lives there and we visit often) I had the catalytic convertors cut off and straigt pipes put in. From disconnecting the battery the codes were lost and we didn't know if only one convertor was bad or both. now the SES light burns all the time. I drove us down and back without too much trouble until we got into town traffic. I was attempting to turn left back onto the highway and when I hit the gas the truck just died. It started right back up and we made it home but we still don't know what the problem really is. The only codes it is throwing now are catalytic converter and O² sensor.

    On a side note, I had a 6 cylinder ford that suffered from that sweet spot syndrom too. It was totaled trying to turn left. I sold it to the junk yard and they put it back together but still couldn't get it to accelerate until by trial and error they replaced the harmonic balancer. It runs great now.
    Now I don't have a lot of money to spend looking for the root of the problem. I need opinions on what the core problem is. The burban drives around town just fine for me. But we need it to be able to make trips too. My husband will not drive it anymore, he thinks the truck doesn't like him. I say it doesn't do it to me because I have experience with vehicles that don't go like they should. To some degree my dodge has this problem too. Mayby it is me:neutral:
    Sorry this is so long
    Thank You in Advance
  2. Toymyster

    Toymyster Rockstar 100 Posts

    Did you changed the dist. rotor along with the cap?? How about your spark plug wires?? While you're at it, a new fuel filter won't hurt, either!!! Change those and see if the problem still persists!!!
    Good Luck
  3. Stand On It

    Stand On It New Member


    We changed ditributer cap and rotor back in Aug. Also changed the fuel filter (I forgot about that) Changed plug wires about 2 weeks later. We still have problems. I currently have the battery unhooked because I just found out I have to drive to Wilmington in a few hours and I want to see how long it takes for the SES light to come back on.
    Thanks for your response
  4. Davandy

    Davandy Moderator 5+ Years ROTM Winner 1000 Posts

    Welcome to the site :sign0016:

    At first it could be something electronic, like the Map sensor or Maf sensor.
    A good workshop must be able to check this for you.
    There are so many sensors on ODBII it's an expensive try and error to replace them all.:no:
    1 person likes this.
  5. Skarch

    Skarch Rockstar 100 Posts

    I agree with Davandy.... First off, you need to put CAT's back in the thing, they are not that expensive and mean a TON to the environment. Second, what I think is happening to you is that you are getting conflicting readings from the intake and exhaust. My GTI had this problem and it ended up being the EGR valve, but the MAF does it to. When you push the throttle, the computer gets confusing readings and can either over or under fule the truck, causing bogging and sometimes stalls. My advice would be to replace the O2 sensors, and then check the readings on the MAF, MAP, etc... untill you find the culprit.

    Good luck, and let us know if you figure it out.
  6. Stand On It

    Stand On It New Member

    I made it to Wilmington and back (about 120 miles) without any problem but the SES light came back on about 10 min into the trip.

    I don't know what a MAP or a MAF is. You will have to explain that to me. I understood the 'confusing the computer' part.

    Expensive is a very relative term, the dealership wants almost $800. to replace the catalytic convertor. We woln't have that kind of money until Christmas Bonus time. It is my intention to replace them eventually. We cut them off soley to determine if backpressure was the culprit, like in a jake brake.

    I was really hopeing to sell my Dodge for the money to do much needed maintence and help us catch up but I can't even get ½ the book value for it.

    So O² sensors (according to advanced auto's web site) are between $50. and $85. each, and it says I need 2. Is replacing them relatively simple, like a ½ hour job? Or is it complicated and better to pay someone else to do? Also will replacing them do any good if I haven't replaced the convertor yet?

    Thank You All for Your Responses
  7. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    When you get ready to put the cats back, skip the dealer and check with your local muffler shop. eBay has cats for as low as $68 each.
  8. BadBurb355

    BadBurb355 New Member

    I do agree that it maybe the EGR Valve or combination of vacuum leaks from old lines. I had a 91 with simular problems, engine vacuum makes a big difference. You also will get lots of codes if you have remove parts (such as cats) because engine computer monitors exhaust before and after the catalytic convertors but I dont think that would cause your problem, but it will make it more difficult to diagnose. Have you ever replaced the Air Filter?

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