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Loss of power...engine stalls....help me

Discussion in '1st Gen. Tacomas' started by eganx, Aug 27, 2010.

  1. eganx

    eganx [OP] Well-Known Member

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    So I have a 99 tacoma, with a 3.4. I noticed it was running rough upon start up, lacked power, would buck if I tried to drive it. But after it warmed up was fine. This has grown into a major loss of power to where I am crawling up hills. If the engine is warm, I can floor it, the engine will bog and then accelerate, and as it revs the actual power will fluctuate greatly. As the RPMs increase the exaust pops/sputter and backfires. The truck is barley drivable.

    So.... no codes are thrown, spark plugs and wires are good, 02 sensor tested good, I cleaned the MAF sensor. I don't get it...if there were a misfire there would be a code, if a sensor was bad there would be a code....WTF? I am about to test the voltage from the TPS. I have yet to put a fuel pressure gauge on it, which will be my next step.

    Any advise???? I need to have my truck back up and running as it is my DD, and I can't take it to a shop since I make shit for money. HELP
     
  2. TacoMo510

    TacoMo510 newb

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    i had a problem where the engine would start up but die right away and only if i gave it a little gas for a minute or two would it keep going. and even then the rpm's would be too low. cleaned the throttle body with a little carb n choke cleaner and my problem faded away. i also didn't get any codes.

    start with giving the throttle body a good cleaning and then go from there. some people are picky with the cleaner that they use, they say that you're only supposed to use throttle body cleaner. but the carb n choke cleaner worked fine for me, just make sure to take the throttle body all the way off and make sure it dries off before installing.

    hope this helps.
     
  3. TacoMo510

    TacoMo510 newb

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    also, if you do clean the throttle body, make sure to get the gasket before hand, just in case you mess up the one that's on there.

    heck, go ahead and just buy a new one, they're only like $2.
     
  4. SkyHighTacoma

    SkyHighTacoma White Tank

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    Some mods. Check build.
    And maybe try seafoam.:)
     
  5. Barnone

    Barnone Guest

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    Plugged cat? Might take it off to see it that's the problem.
     
  6. rcbs204

    rcbs204 Well-Known Member Vendor

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    Its your Fuel pump bro, guarantee it.
    Edit: So listen man, i have a fuel pump that came out of my 95, it was in good working order when i removed it. It was replaced with a high flow for the super charger. Anyway if you need it, its yours, you just pay shipping.
    Cheers,
     
  7. eganx

    eganx [OP] Well-Known Member

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    the throttle body is clean...cleaned it out about 6 months ago. Thought about the plugged cat....the one under my truck is welded in. I am thinking about cutting it out.... if I cut it out to see if its clogged its not going back in either way.

    I'm leaning toward the fuel pump. There isn't anywhere I can borrow/rent a fuel pressure gauge......so I'm going to have to probably get a cheap on online.....
     
  8. kevhogaz

    kevhogaz Low Speed, High Drag

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    Sounds like an Air Flow Meter, to me. Try cleaning yours, before you rip the cat out.
     
  9. nvdeserted

    nvdeserted Well-Known Member

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    As mentioned before, I'd first check the fuel pressure and the throttle body.

    Check the airfilter for rodent/insect damage. They will go in there and shred your filter, the little bits will clog/confuse your airflow sensor and cause the power to fluctuate and vanish.

    It sounds like you have spark, check the fuel and air.
     
  10. eganx

    eganx [OP] Well-Known Member

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    as I stated in my OP " I cleaned the MAF sensor"

    I had to take my air filter out to clean the MAF and it was fine. I'm trying to find a fuel pressure gauge to borrow........until I can test the fuel pressure I can't really proceed much further
     
  11. Manlaan

    Manlaan Well-Known Member

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    You didn't mention changing your fuel filter, which would be a quick fix on the 3.4L. If its never been done before, I'd suspect its probably about time anyway. If your fuel pressure tests low, you'll end up replacing it anyway just to be certain thats not the cause.


    For a fuel pressure tester, I'd just go pick up a cheap one at Harbor Freight. Its not the best, but if you use teflon tape on the threads, it should be able to give you a go/no go for pressure values easy enough. For a one time use item, the price and quality really isn't that bad.

    Also, have you checked your local auto part stores to see if they rent one? Probably not due to different fuels and such, but its worth a shot.
     
  12. eganx

    eganx [OP] Well-Known Member

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    fuel filter was replaced 6 months ago. I thought about harbor freight but the closest one is a hour and a half away. None of the autoparts stores rent/loan one, and the cheapest one in an autoparts store I could find was $50....which I don't have to spend on that at the moment
     
  13. Manlaan

    Manlaan Well-Known Member

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    Well, its not as exact, but since a fuel pump is also measured in gals/hour (liters/hour), you could also measure the amount of fuel that comes out of the feed line for a small duration. I couldn't easily find what our stock pumps are rated at though.
     
  14. eganx

    eganx [OP] Well-Known Member

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    good point.....but I sold a car today(a car I bought to flip)so I will have a little extra cash.....fuel pressure test gauge here I come.

     
  15. eganx

    eganx [OP] Well-Known Member

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    so what about the three coils........I have yet to test these. Anyone have any experience with these going bad? Anyone know the resistance specs on these????
     
  16. swsteven

    swsteven Well-Known Member

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    fuel pump or bad gas
     
  17. eganx

    eganx [OP] Well-Known Member

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    thanks for the diagnosis big chief

    Update - checked resistance of all three coils....all are good

    could some carbon have made its way into the idle air valve on the bottom of the throttle body???

    I am also thinking the MAF could be bad.....I'm going to hook up my computer and watch the fuel trim....
     
  18. eganx

    eganx [OP] Well-Known Member

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    The long term fuel trim was -13%....which mean the computer was deducting 13% of the fuel from the map, AKA the truck is running rich. So I now have to check fuel pressure to see if its a bad fuel pressure regulator, bad vacuum line to the FPR, pinched fuel return line etc......and if the fuel pressure is fine then my bet is the MAF is giving a false reading telling the ECU the engine is breathing more air than it really is....
     
  19. NW4RUNNER

    NW4RUNNER Well-Known Member

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    Any diagnosis for this? My 3.4 is sporadically stalling under load after shifting. I'm s/c with 7th inj, new plugs and fuel pump. Feels like throttle related since truck doesn't seem to be pinging. Any ideas? Also no CEL.
     
  20. BamaToy1997

    BamaToy1997 ASE Master Tech Vendor

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    You are correct that -13% is resulting is a reduction in fuel provided by the injectors. HOWEVER that fuel trim number is only an indication of several problems. Yes, you could have a MAF sensor that is bad, but you could also have a bad AF sensor that is incorrectly reading the O2 levels. You could have an injector that is leaking and causing a rich condition...etc. I know that you said you have limited funds, but replacing this part and that part gets really expensive fast. Sometimes it is best to take it in to a professional, and be honest with him. Tell him you need a diagnosis and that you will pay him for his time (Usually between $25 and $75) and find out what IS wrong, and then replace/repair a single problem, yourself, one time.
     
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