Regaining Lost Power

Discussion in 'GM Powertrain' started by BajaMark, Jul 2, 2012.

  1. BajaMark

    BajaMark Member

    Im sure this is a standard question, but I was unable to find a relevant thread if someone can point me in the right direction. I have a 99 Silverado 5.3L with about 160K miles which seems to have lost A LOT of its power, specifically while towing (21' boat). What is the best course of action, things to check/change/add. All standard maintenance has been kept up including oil, air filter, fuel filter, etc. I was looking at programmers, unfortunately CA legal, but did not want to go this route if there was a mechanical issue that needs to be addressed first. Im on a very limited budget and just trying to explore my options. Thanks for any help.

    99'HEARTBEAT MODERATOR Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    Next to what you have Mentioned regarding the maintenance, do you have any Aftermarket Performance Mods installed on your Silverado??....and do you have Larger aftermarket Rims/Tires and last what Rear Gears does your Truck have??
  3. BajaMark

    BajaMark Member

    It has a K&N intake, Flowmaster muffler, and its lifted 4" with 17" rims and oversized BFG All Terrains, not exactly sure of the size. I'm not 100% sure but I believe my gear ratio is 3.73, my rear end went out and was replaced with the same ratio just without posi due to $$. It does throw out a 420 code every once in a while, but I use my scan guage to just clear it. Ive tried replacing both O2 censors front and back of cat with no success, and can't really afford to replace my cats. I was told that code will only effect gas mileage though?
  4. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    You've created additional arodynamic drag by lifting the truck, so now it has to fight against the wind a little more. If you removed the front valance for that tougher look you also added some more drag, there. Then there's the tires: bigger tires equal more weight to get moving, which again, impacts performance.

    The short answer, here, is that you need shorter gears for the lift and tires you've chosen to run. How short? That depends on your tire size and driving habits. Rather than repost a pile of information we already have on the forum, I'll simply refer you to a thread in which I recently supplied some data you can use for your own edification. Find my first post in this thread:
  5. BajaMark

    BajaMark Member

    Thanks for the reply and very helpful information. I will check the tire size/gear ratio tomorrow. I think changing gears will be something I look into in the near future if I continue to tow with this vehicle, but with the 4x4 it will wait. Any suggested tuners at a economical price that will bring me close to my performance goal that are CA legal. I will be PCS'ing to VA in December, so maybe I will hold off for the Diablo in tune tuner...

Share This Page

Newest Gallery Photos