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1998 chevrolet 5.7 engine mis

Discussion in 'Chevy C/K Truck Forum' started by Grahamwk, Jan 15, 2014.

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  1. Grahamwk

    Grahamwk New Member

    I have a 1998 chevrolet 5.7 that has a miss that I can not get rid of. The miss happens when I lightly press the gas pedal whether I am at a high speed or a low speed and it has even started doing it when I floor it. It sputters, lightly jerks right before the gears shift and misses. There are no codes up, I can hear my fuel pump cut on and the truck has 210k on it. I have listed below all of the parts that I have changed in the past 5 months….

    Ignition coil
    Distributor cap and rotar
    Spark plugs and wires
    Map sensor
    throttle position sensor
    Egr valve
    Pvc valve
    starter
    wiring harness
    new battery
    195 thermostat
    MAF sensor..
    I also cleaned the idle sensor and the throttle body itself.




    I have no idea what else to do to take care of this mis, any ideas anybody? I would greatly appreciate it!
     
  2. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    Im gonna follow this...
     
  3. TRPLXL2

    TRPLXL2 Epic Member 5+ Years 1000 Posts Platinum Contributor

    Welcome to the site!!

    Did you reset the iac after you cleaned it?
     
  4. Grahamwk

    Grahamwk New Member

    Actually I was unaware that it needed to be reset, How would I go about the reset? I also put on a new ignition control module yesterday and swapped the fuel pump and starter relays out to see if there is a difference, not sure if I needed one but the truck is pretty old so I figured it wouldn't hurt.

    - - - Updated - - -

    I also just read that I would need to adjust the throttle position sensor after resetting this IAC?

    - - - Updated - - -

    I am very glad that I found this site, I have looked all over the net for possibilities on what the problem could be and have hit a dead end every time. I just filled up with gas and added a fuel injector cleaner to the tank and went driving for a little bit. I noticed there isn't a pattern to the misses. I also noticed it sputters,misses and jerks mostly when barely applying the gas or letting off on acceleration and decell. It makes more of a popping noise when accelerating and sometimes jerks with it. Sometimes it sounds like pop…pop….pop… while other times especially when I floor it sounds more of like pop,pop,pop,pop,pop…………..pop,pop,pop,pop,pop with clusters of the same popping noise

    - - - Updated - - -

    I just went out to my truck and tried to start it. It has been months since it was hard to start and it took me three tries and as soon as I got the truck running it finally threw a code P1351. I went and had the code removed to see if it would come back on and it hasn't yet. The truck still runs like ass haha, what a day!
     
    Last edited: Jan 17, 2014
  5. TRPLXL2

    TRPLXL2 Epic Member 5+ Years 1000 Posts Platinum Contributor

    Turn the ignition on and let sit for 15 seconds
    turn the ignition off for 30 seconds
    turn the ignition on, and hold the gas pedal down about half way
    start the vehicle, and let off the gas pedal
    let the vehicle run for 5 minutes
    shut the vehicle off
    turn the ignition on for 30 seconds
    turn the ignition off, and it should be reset.
     
  6. Grahamwk

    Grahamwk New Member

    I did it in that exact order and then let it sit for about an hour. Later I got I noticed that it ran particularly better than before, until it got hot. I pulled over, popped the hood and noticed every spark plug was miss firing..... I guess I will replace them again, then update
     
  7. Jamm3r

    Jamm3r Member 1 Year 100 Posts

    The two strongest possibilities at this point are the fuel pump and the fuel pressure regulator. Finding the problem will take some equipment.

    You can measure the fuel pressure at the "rail" -- really just a point before the place where the fuel line dives into the intake manifold -- with a gauge. Buy the gauge at any auto parts place, they're not expensive. I can't remember the spec but it's around 60 psi and should stay their fairly consistently.

    If that's ok then use your obd-ii reader to watch the fuel trims while you drive. If you do not have an obd-ii reader that will do this you can get Torque for any Andriod smartfone, for free, and buy a bluetooth obd-ii cable for around $60. Borrow a smartfone from a friend.

    Anyway if the fuel trims are running lean then there's a good chance that the fuel pressure regulator is leaking. It's a common problem in 5.7s with fuel injection. Replacement unfortunately requires removing the intake plenum. Not impossible but not an easy job, lots of videos on youtube to show how it's done.

    Good luck
     
  8. Grahamwk

    Grahamwk New Member

    Thank you so much for the ideas. I thought before that it might be the FPR and thought about replacing it but the symptoms that I found didn't fit the problem. I really hope that it isn't the fuel pump,but if it is maybe just one more good hit to my bank account and my truck will run good again. I will try them both an post my results. On a lighter note, I replace the plugs and wires for the second time in 6 months and the old ones were a little darker on the tips with a little build up. The truck unfortunately still runs like **** and it even threw me a code of P1351 ignition control circuit high voltage, which is weird because I just bought that ignition coil so I am, not sure as to what it is crying about
     
  9. Grahamwk

    Grahamwk New Member

    Just an update, The code was from a faulty ICM so I got another one put on and the code went away but the mis did not. I am at a complete loss now and have no idea. I guess I will take off the FPR and check it out along with the injectors, is manual cleaning an option for either one of these parts or is it just one of those replace situations? Also I noticed in the fuse box under the hood that there was a empty spot in the fuel sol fuse spot and the aux fan fuse spot, does this hurt anything? I am just curious because I bought it well used. I am also thinking about cleaning the cam sensor but can't find it?
     
  10. Scott_Anderson

    Scott_Anderson Member 2 Years 100 Posts

    These things come to my mind as I read thru the posts here.
    1, at 210K miles it's possible your injectors could be worn and not spraying evenly.
    2, how is your oil consumption. Have you done a compression test.
    3, how long since you changed your fuel filter.
     

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