By on July 9, 2014

M.D.K. writes:


I am currently at Bagram Airfield in Afghanistan where I will often find myself motoring around the Forward Operating Base (FOB) in one of the last generation Chevy Trailblazers. It is the straight six variety and it has undoubtedly led a difficult life. My requirements are few however…pretty much I need something that can do 25 miles an hour or so and not strand me on the other side of the airfield. As a bonus, the Trailblazer has a working AC and radio. What it doesn’t have is the ability to do 25 or so miles an hour regularly and get me back from the other side of the airfield.

Pressing the gas pedal beyond a few millimeters will get me stalling and/or backfiring. In general it sounds like it is running on 4 cylinders. It will surge and run normally for a second and then not. It seems to get worse the hotter it is (which is bad this time of year.) I took the damn thing to the motorpool and they told me I can turn it in and walk back if I don’t like it (the drawdown is a mother). I had to jump out and push it up the little ramp into our compound as it lacked the power to accomplish this feat on its own. As a Ford guy, I get some amusement out of this and taunting the Chevy fans but the fact is we could really use this thing. A bunch of us IT types have stared under the hood for some time and haven’t figured anything out. I am mechanically inclined (I’ve changed motors and stuff before) so I think I am the truck’s last hope.

This thing would be the nicest vehicle in our fleet by virtue of the AC if it would run. No, I can’t pull the damn codes as the PX is short on OBDII readers (and toilet paper) and there isn’t an Autozone within 7000 miles or so. If this may be something simple like a fuel filter or something I’m willing to get some parts sent over and crawl under myself. Just need to know if there are any common issues with these things. I don’t see any major mechanical issues like overheating or oil in the coolant. I appreciate your input.


Sajeev answers:

So…no professional diagnostic tools, no basic Autozone diagnostic tools, and you’re the truck’s last hope? And an LS1-FTW swap is totally out of the question?

Checking the forums, it’s possible that a cam position actuator solenoid is the problem…and it will not throw a code.  Or maybe a dirty throttle body, a clogged fuel filter or a dirty air filter.  If the fuel you receive out there isn’t the highest quality, the filter is a major concern.  And maybe your IT folks have electronic contact cleaner to clean the throttle body AND the mass air flow meter. But I’m all over the map: here’s my plan of action, given limited resources:

  1. Replace fuel filter, if other vehicles need regular filter changes out in the field.
  2. Shake out the air filter, bumping it on a large surface. Don’t bang it against a wall hard enough to damage it. I find large plastic garbage cans work well here.
  3. Clean the mass air flow meter and throttle body with electronic contact cleaner.
  4. Pull the spark plugs, clean and gap them.
  5. Replace the Cam Position Actuator Solenoid: even Amazon stocks them, maybe one of their drone prototypes can deliver it.

I will keep my fingers crossed that bad gas and dusty air are your only problems.

But no matter what, thank you for writing to us and thank you for your service.  

Send your queries to [email protected]com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.


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29 Comments on “Piston Slap: The Last Afghani Trail to Blaze...”

  • avatar

    “I took the damn thing to the motorpool and they told me I can turn it in and walk back if I don’t like it.”

    Unfortunately this will be good training for our poor MDK to prepare him for when he gets back to the states and needs health care from the VA. It’s bad enough he has to drive a Trailblazer in any condition; a poorly running Trailblazer in Afghanistan must be automotive hell.

    Good luck,get home soon.

  • avatar

    I see the Motorpool guys haven’t changed much since my Grandfathers day.

    He had to bribe them with a case of air rations to get them to fix the truck he needed.

    • 0 avatar

      Isn’t that their… job? I thought things ran much more smoothly than this SOL type response.

      • 0 avatar

        “Welcome to the United States Army privates. If you don’t like it, you can go [email protected] yourselves. Can I get a Hooah?!?”

        -Day 1 at the 30th AG Reception Battalion in Fort Benning, GA (June 3nd, 2003)-

        • 0 avatar

          At least I never wondered whether I would enjoy being in the military or not.

          • 0 avatar

            Yeah, that is before going down range to basic training. Some people love the lifestyle though. Who doesn’t want to get 3 divorces or date a stripper that is married to a real piece of work Sergeant that will bust you down a rank?

            Being an officer is much better. I wouldn’t mind going to OCS and having my wife, who is an Occupational Therapist, sign up as well. The only problem is I don’t need her outranking me at work, and at home.

          • 0 avatar

            Was that your experience with strippers and divorce!?

            My sister is an OT. She really likes it, and makes great money.

          • 0 avatar

            No. I had a relatively uneventful personal life while in the Army. Being deployed all the time will do that. A friend that was in the Marines was busted dowm in rank for dating a superior’s wife, who was also a stripper. I knew plenty of guys that got divorced more than once while enlisted. I think divorce is more common than not in the US Military.

          • 0 avatar

            I’ve heard that about divorce in the service. If this is a known hazard then why do people get married in the first place? Additional Army bennies?

          • 0 avatar

            Lots more bennies and much better housing. You don’t have to love your wife, and she might even be a lesbian or something*.

            *True story.

          • 0 avatar

            Ah. Seems like such a policy is only going to encourage bad behavior.

        • 0 avatar

          That’s funny. I arrived there 20 May 2003. 32 and overweight, still recovering from a broken ankle. Left looking a lot different in September……

          • 0 avatar

            CoreyDL – did I know you in about 1993? Friend’s wife was “wandering” on him while we were working. She had a girlfriend and eventually left him.

            In my time in the military about half of my married peers went through a divorce. A good portion of the still married folks were playing the field as was their spouse.

            This all figured into my reasons for a single enlistment (albeit long). Wanted to settle down and I didn’t see it as an easy place to balance married life and raise kids and meet the expectations of Uncle Sam.

            As for the Trailblazer – I would guess a massive vacuum leak somewhere or a crank angle sensor going bad?

            Safe trip home fella.

          • 0 avatar


            In 1993 I was 7. So probably no.

  • avatar

    I would also check to see if the cat is plugged/melted down. Usually you can unbolt it enough to see if it will make a difference.

    • 0 avatar

      ^ This is my vote, based on similar “light-gas OK, anything else is horrible” symptoms.

      I had a Z28 where I naively thought I lost half my cylinders. Turns out the cat simply shattered and clogged the pipes. If you un-bolt the pipe ahead of the cat you can at least see if it’s worth hogging out the cat with an air chisel….

  • avatar
    Mr. K

    1) Dirty, gummed up throttle body plate.
    -Clean with carb cleaner approved for this use – use bad stuiff and you might knock out the mass air flow meter. Even wiping the gunk out might help enough to get it running smoothly.

    2) Less likely but throttle position sensor.
    — replace throttle position sensor.

    Codes would help a whole lot – without them this is just a guess, as is my guess that the fuel filter is not causing the problem, but might be due for replacement anyway based upon the description of the PM regime. …

    • 0 avatar

      I bought an OBDII scanner than talks wirelessly to my Android powered tablet. Was about $20 for the scanner and another $20 for the software. Torque is the app and Amazon (among others) sells compatible scanners.

  • avatar

    I am of the school of thought that it is carbon plugged from the low speed low mileage routine. Take the brake vacuum hose, get a spray bottle of water and start spraying. Have a competent person on the throttle and keep it going until it smooths out – relatively speaking. I would concur with the fellow Lincoln owner on the other ideas, too, but carbon loading on your valves would be one explanation for poor power as you would have low compression. If you were to do all the listed remedies and the condition persists, you do have access to some way cool explosives, right?

  • avatar

    I am in Bagram also as a contractor and we have unending issues with vehicles. Don’t overthink this…’s probably a case of some knucklehead putting diesel in a gas vehicle…the only vehicles that hold up over here are 5 speed Toyota Hiluxes and maybe old Ford (Mazda) diesel pickups. All the American iron is scrapped after a couple years. Usually to fuel issues. Take a look at the size of a Hilux air filter if you doubt their suitability to this environment…they are huge. I wish I could buy a Hilux in the US…toughest truck on the planet…and they make a great “technical”!

  • avatar

    Oh for… You’re in a group of IT guys. What do you have that the guys in the motorpool want / (within reason here) need? offer or deprive as required. Done right, you get a new friend and share stuff. It’s a life skill anywhere, doubly so in the service. Do what you can on your own, it will help with the respect required to set up this black market transaction. It won’t be hard, you have better porn then they do.

  • avatar

    Without codes, my best guess would be a large vacuum leak somewhere. Listen for a large whistling noise around the engine. If that doesn’t find it, start spraying areas of the intake with carb cleaner or similar while running. When the engine rpm changes, you sprayed it into the leak.

  • avatar

    You’re in IT so why not make a serial->OBD2 cable?

  • avatar

    Dirty fuel could be the cause of blocked injectors to, and, by now the plugs are fowled up.
    Best solution here is to get the vehicle into a shop or secure a Toyota Hi-Lux for your use.

  • avatar

    Got a android device with bluetooth? If yes, Access to Wifi, if yes. Send me your address and I will mail you a ELM327. Or you can get one on Amazon for a few dollars. You need to snatch torque pro. If you need the 6 bucks .. I will help.

    Best I can do.

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