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4.2l

  1. Second replaced coil pack in one month

    OEM Issues
    About a month ago we got a check engine light and very rough idle. The code indicated misfire on cylinder 4. I replaced the spark plugs and cleaned the throttle body, but that didn't help at all. I then replaced coil pack # 4 and it worked fine. I cleared the code and it didn't come back. A few...
  2. [SOLVED] 2002-2005 Alternator on a 2006 Trailblazer 4.2 LS

    The "How-To" and DIY Section
    I can't really seem to get a fix on why a 2005 Alternator can't be fit on a 2006 Trailblazer 4.2L LS. Is it the amps? The bracket? The connector? 2006 Trailblazer is out on an Island as the 2007-09 also do not retro. I want to fit one of those HO Alts but most only go to 2005.
  3. Exhaust

    Exhaust Mods
    I am stuck with the stock exhaust right now and am looking towards getting an aftermarket muffler such as a flowmaster or borla. I am a teenager and do not get paid much so i cant afford a full exhaust. I do not mind sound, in fact id like to have it fairly loud just not too loud to where I have...
  4. Broken spark plug ... HELP!!!

    General
    Hi all ~ I did the unthinkable ... while changing the plugs on the 4.2L engine on my 06 Envoy, the #2 plug broke in half with the threads remaining in the engine. I'm not a mechanic by trade so changing oil and plugs are the only thing that I would even attempt on my own. This is the first time...
  5. What kind of mods to do for power? (4.2L i6)

    Engine Tunes/Mods
    Hey i have a 2004 TB LT, with a CAI and Performance chip. What other mods can i do to make some more HP? Have yet to see someone turbo the blazer, so what other mods is there?
  6. A Magic unknown problem with my trailblazer need help

    Introductions
    Hey my fellow trailblazers I need help big time. My trailblazer, an '06 4.2 lt, is acting up, and I have no idea what the problem is. When I start driving highway speed, my whole car starts to shake inside and out, and i feel the brake pulsate when I press on them, also does this when i reverse...
  7. How to replace Spark Plugs (pics)

    OEM Issues
    As this forum gave me so much in learning about my vehicle, I thought I'd go ahead and give something back, and document my new found knowledge and show you the steps on how to change your 4.2L I-6 Spark Plugs. Note: Common sense would dictate that you go ahead and do a throttle body cleaning...
  8. Tuning Rochester NY O2 problem

    Engine Tunes/Mods
    I have a 2004 Trailblazer 4.2L I6 and was wondering if anyone had a tuner or know where I can get the truck tuned. I have been having problems with my O2 sensor throwing a code. I have 110000 miles on the truck and recently put a new catalytic converter and o2 sensor in the truck. Everything was...
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