new to GMC can anyone help?

Discussion in 'General Chevy & GM Tech Questions' started by k_lakey, Mar 11, 2009.

  1. k_lakey

    k_lakey New Member

    i just got a 1990 gmc stepside 4x4 with a 5.7 a 4' lift and 33's on it and when i drive it feels realy slugish... its got a magnaflow cat back... take off is really slow.. can anyone help?
  2. GaryL

    GaryL Epic Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    Welcome to the site.

    Do you know what gears you have in it? It sounds like you may not have enough gearing for the size tires you are running.

    You might also check the timing, if it is off it could cause sluggishness.
  3. bry2500

    bry2500 Epic Member 5+ Years 1000 Posts

    I would agree about the timing, 33's are not significantly over sized so IMO they are less of a factor here. Still if the gearing has been changed from stock before then they become more of an issue.
  4. retired2001

    retired2001 Epic Member 5+ Years 5000 Posts

    Welcome to the site. You didn't mention, but considering the age of the truck you might want to check out the catalitic converters. They can cause a lot of issues when they go bad. Just a thought.
  5. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    Make sure to have it scanned for codes. There may be a code stored in memory that can point to the power loss.
  6. k_lakey

    k_lakey New Member

    i dont know what gears are in it... i think stock
  7. k_lakey

    k_lakey New Member

    and the catalitic converters looks new
  8. ct9a

    ct9a Epic Member 5+ Years 1000 Posts

    An easy way to check the cat is by temperature. I picked up a cheap laser thermometer at Harbor Freight when I thought mine was going out.
  9. k_lakey

    k_lakey New Member

    how would i do this?
  10. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    Easiest way is to take it to Autozone. They will scan it for you for free.

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