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07 Silverado 5.3L feels sluggish

Discussion in 'Performance & Fuel' started by mah2496, Aug 24, 2010.

  1. mah2496

    mah2496 Member

    My 07 Silverado NBS performance feels like it has gotten sluggish lately. 5.3L all stock except for K&N filter and slightly larger tires. I've put roughly 85k miles on it. Engine fans (electric type) seem to run alot if temp is mid 90's or higher. Any thoughts or suggestions?
  2. 99'HEARTBEAT

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



    Went you mean Sluggish.....all the time and/or at certain speeds??.....What size tires did you put on....also what Rear Gears do you have....
    Last edited: Aug 24, 2010
  3. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    The electric fans turn on when the a/c is turned on, so if its in the mid 90's I assume you have the a/c on?? Also what '99Heartbeat ask about tire size and sluggishness.
  4. mah2496

    mah2496 Member

    Sluggish more so off the line, especially when it's hot. I'm not interested in racing, but it used to have better pep. 3.42 gears with 285-60 on stock 18 wheels.
  5. hundojoe

    hundojoe Rockstar 100 Posts

    Its normal for an engine to get sluggish when it gets hot, heat is the enemy, the more heat you can extract from the engine bay the better you truck will run. Also when you are running the ac not only does the compressor put extra load on the engine the electric fans are also putting an extra load on the alternator which also puts more load on the motor.
  6. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    OK, you have factory 3.42 gears. The stock tires were most likely 265/70-17's. The 285's tires are taller and so the truck acts like it has 3.23 gears. Also did you reprogram the trucks ecm for the taller tires?
  7. mah2496

    mah2496 Member

    The stock tires were actually 265/65-18 (Z71 wheels). Therefore, my stock tires were actually a bit taller than my 285. I have not reprogrammed. Could catalytic converter(s) be bad?
  8. JennaBear

    JennaBear Rockstar 100 Posts

    Clean your MAF.
  9. mah2496

    mah2496 Member

    What do you use to clean the MAF?
  10. Metaluzc

    Metaluzc Rockstar 4 Years 100 Posts

    You can get a can of CRC MAF Sensor cleaner at autozone, it's about $7. Also get a can of CRC Throttle Body & Air Intake cleaner as well. Your throttle body could have some major build up of carbon since you have already put 85k miles on an '07. I recently cleaned the throttle body and MAF sensor and my truck runs 100% better and I only have 80,6XX on my '03.

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