Chevy Trailblazer 4.2L I6 Mail Order Tune

(22 customer reviews)


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Our performance tuning for the 4.2L I6 typically yields 10-14hp and 1-3mpg, as well as better throttle response, driveability, and more pep off the line. Our tuning also helps with towing if you choose to do so. We can account for most modifications you might have (2002-2005 year models: we are not able to make speedometer corrections or remove park/neutral rev limiter). After placing your order, please click on fill out an order sheet for your vehicle (here). What program should I use and what is refundable? Click here!  Express shipping only covers one shipment for loaner programs, the second will be returned via UPS Ground unless other arrangements are made.

How to mail in your ECM – CLICK HERE.

Please note, 08+ Automatics will have a transmission control module also, if sending in your PCM please include this.

Also, check out our Aeroforce Scan Gauge  – not only is this a helpful gauge for scanning many parameters, but it is capable of performing the CASE Relearn as well (if you are doing a core program).

Additional information

Weight 4 lbs
Dimensions 9 × 8 × 4 in

22 reviews for Chevy Trailblazer 4.2L I6 Mail Order Tune

  1. Mich

    I waited for years to order my PCM tune…

    It came today and I could barely control myself. I came right home and installed it. I started the truck up and went for a drive. I noticed right away that the gas pedal was much more responsive and I could feel more power. The shifts were much much nicer.

    First impressions: HOLY SH*T! I started out my going to a straight stretch of road with no traffic. I came to a complete stop, and then dropped the hammer. For the first time EVER, I left rubber on the road from a standstill I couldnt believe the throttle response, it REALLY pulls now. It feels like a throttle governor was removed.

    All in all, what an improvement. I also noticed that, even though I dropped the hammer twice, my average mpg’s were up from earlier today…lol. I think Im going to like this!

    Hats off to PCM, the really fast service, the excellent communications – emails are responded to immediately, and for "waking up" my Envoy!!

  2. Thomas

    Kelly, I would like to thank you and Marshall for a job well done! I am extremely pleased with my tuned PCM. The SES light is gone and I can hear and feel a snappier shift in my truck. Thanks again!

  3. Tony C.

    Nice smooth acceleration and slightly better throttle response after I got to take it on the highway. Shifts awesome, nice downshift sensitivity and slightly better throttle response. Thanks again from a great tune. You’ve got my loyalty and the loaner is in the mail. I’ve also included an attachment of my under-hood, please check it out.

    Thanks again and grateful,

    Tony C. PCMofNC fan

  4. Austin W.

    The truck runs great. Thanks for waking up my Trailblazer.

  5. Jason

    Got my tune today. 2005 4×4 i6 Trailblazer. octane 89,shift fimness 2,no towing. Truck is much more responsive!!!! The shifts are perfect,not too soft,not too hard. Great job guys!!!

  6. John M

    Finally got around to getting my PCM tuned (2003 4×4 I6) everything across the board is better IMO. better throttle response, accel, gained 1-2mpg. deleted codes so next up is efans. I have a level 2 shift firmness and for me its not aggressive enough. lol I daily drive it and tote my 1 year old every morning with no issues ( but I also come from a background of tuned Subaru’s so some may like the firmness 2 or under) all around its made me actually enjoy my TB!! If your on the fence i’d recommend it doing it! Thanks again guys for your hard work and helping us I6 guys out!! Fan/customer for life!

  7. Jarron

    I’ve had my tune for a couple weeks now. Not to sure on gas mileage due to smashing the pedal more! I have shift firmness 2 which is just right for my EXT LS. Throttle response is incredible. When you hit the gas all the power is right there and not lacking. Shifting and highway drive truly impresses me every time now. Don’t have to floor it to pass either! Barely push gas and you get more than 2 shift points for passing and when you punch it you get high RPM’s for faster acceleration! Very pleased with my mail order tune… My Trailblazer is ALIVE!

  8. James M.

    Just a quick email to say I installed the PCM on Sunday and it has been working like a charm ever since. Thanks for your quick turn around, I will definitely recommend your business to others.

  9. John W.

    I put it back in today and took it for a drive, I can’t tell you how happy I am. I just wanted to let you know. Thank y’all so very much!

  10. Joe S.

    i sent the loaner pcm back to you guys today. my truck runs great. thank you very much.

  11. John M

    This is my second time around with getting a PCM tune with these guys. First car was totaled out within a month by a uninsured motorist after getting a tune, 🙁 This time around I have an 06 EXT LT and all I have to say is "my small bus now has a set of balls!" I increased the shift firmness from 2 to 3 and man she kicks when you mash it!! So again, thanks for the tune and GREAT customer service!!!

  12. Chad B.

    Everyone at PCM of NC

    I can’t thank you enough for the tune that I received. Its more then I truly expected. The responsiveness of the truck has returned. The day I ordered my pcm tune (8/8) I was at the car wash and I just turned on the AC and my truck kicked a code (P0060). It basicly said my PCM was going out. I had been having issues with it all summer. So, this was the time to order a new one with a tune. But I wanted to say thank you.

  13. Garrett

    I was on the fence about getting a tune, but I’m glad I did. It’s been a month since I had my 05 tb 4×4 tuned and I have noticed a 2 mpg improvement, throttle response is much more crisp, and shifts are firm. I ordered mine with shift level 2, 89 octane, some light towing, no mods, and it’s worth every penny. I tow a small speed boat on occasion and the towing characteristics have improved dramatically . Being a technician at a local dealer, i like to keep my daily driver rather stock, but this is a mod that I love. It totally changes the feel of the once sluggish 4.2 I6. I would recommend this to anyone that wants less torque management in their gm vehicle.

  14. Marco P.

    The tune was more than what I expected! The response is a lot greater and the difference is felt with acceleration and gear shifting. I will definitely send my future pcms to be tuned by PCM of NC. Great quality product!

  15. Tom McNeal (verified owner)

    I wish I did this years ago. Was worried that it would mess up my TB. I need it for my daily driver. Folks at PCM were great! Quick shipping…no surprises.

    Put the PCM in and was actually able to spin the tires on the TB bus! I also clocked an mpg of 19.5 on premium. Last 3 have been 16mpg on regular. My TB was always getting about 14.

    Now saving up for the e-fan kit.

    Thanks PCM of NC

  16. Derick Gregory (verified owner)

    I just purchased the mail order tune and couldn’t be happier with the customer service and help I recieved! Mark in particular went above and beyond with his service and help! This is a great company to deal with! And what a differance the tune makes!

  17. Carl Brooks (verified owner)

    Thanks for waking up my trailblazer

  18. Gary M Locke (verified owner)

    I have been evaluating the tune-up of my ECM. I have a 2008 Trailblazer that I have been using to tow a 19ft RV. Before the tune, pulling the RV was OK. But it was constantly shifting from OD to Drive. When the ECM and the trans module were both programmed the shifting was eliminated. The truck is so much quicker and smoother. Mileage when towing was 9 MPG. Now it is a little better at 10.5 MPG. I am not complaining!! Disconnect the RV, and the MPG jumps to 15 all day long. I haven’t got a ticket yet. But you have to keep an eye on things, 0 to 60 comes on fast. Customer service is excellent. The return of my ECM was as promised. This looks to be money well spent.

  19. Brian Blythe

    Great customer service in pre-purchase information gathering email exchanges, getting all my questions answered promptly. Can’t wait to get mine!

  20. Fernando Ramirez (verified owner)

    Very impressive results. Great customer service. If you are thinking about this, absolutely do it. Much improved throttle response, more performance at all gears.

  21. Gabriel (verified owner)

    Just got my pcm yesterday installed it and tried it this morning going to work and all I can say is WOW what a difference. At first I didn’t what I want but called and mark from pcm helped me out alot explained what I really need with the parts i already have on my trailblazer 4.2 and it made a big difference in pick up timing and the throttle response pcm has great customer service and they don’t rush anything even if you have a dumb question they will help you out. Thanks mark for everything

  22. Paul Routhier (verified owner)

    Although my 2009 Trailblazer LT 4×4 is mostly my winter vehicle, I always felt it lacked something. The advertised 285 HP always was baffling to me as it was underpowered, especially from a dead stop. After a few years of debating to get this tune, I decided to bite the bullet. I did keep my tune at 87 octane but it still made a big difference.

    Taking off from a stop can be far more aggressive now and the shifting is much more in point. I did select the 2 level firmness and it doesn’t feel over firm at all. Fuel mileage is about the same although I see that getting better the more I use it as the truck doesn’t have to constantly downshift on the highway. Overall a great value based upgrade.

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