First problem...'miss' at higher throttle (updated) - FirebirdV6.com/CamaroV6.com Message Board

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  • First problem...'miss' at higher throttle (updated)

    Had my first problem with my car tonight. Basically, i was driving all night with no problems. Car ran great, it was like 43 degrees outside, and slightly humid, but car ran great. I was leaving a place later in the night, and gave my car about 75% throttle in 2nd gear, and it studdered a bit, although it kept accelerating, but slower. I found this weird, and tried it in third, and it studdered again when i applied anything over 75% throttle.

    So i started doing tests. Here is what i came up with:

    Symptoms:
    Car studders under heavy load (approx. 75% throttle or more in any gear.) Feels like a miss, or something to that nature. More throttle i give it, the more it 'misses', and sometimes i even get a backfire.

    What i did to test this problem:
    Ran it slowly up through the RPM's in each gear. No studdering.
    Gave it about 50% throttle in each gear, and no studdering.
    Only when it is 75% or more, it 'misses'. It is more noticable in lower gears (i.e. first its noticable, 2nd you can notice it even more, 3rd it really studders, and 4th does the same (didnt try 5th)).
    I put it in neutral, and went under the hood and used the throttle to run it up through the RPM's while just sitting there. No miss at all, so this only happens under a load. (i did NOT try to quickly run it up through the RPM's with the car in neutral)

    What i think it could be:
    1) Coil packs? (70K miles, and they are probably the original coils, but i would think the miss would be constant, not only under load)
    2) I washed my car today, including the engine. There was water all over the place. Possibilty that water got into something? (BUT, it ran fine right after i washed it, and for like 6 hours after i washed it, it was also fine.)

    I cant think of anything else.

    Help in getting to the bottom of this is fine. Im going to check the car tommorrow morning and see how it runs, and ill post back. Thanks to anyone who replies in advance.

    Car: 1996 Camaro 3800, M5, only mods are Borla, 3.42's, shifter, thermostat, and some suspension stuff.

    [ February 23, 2004, 05:12 PM: Message edited by: Ian ]

  • #2
    i had a cracked spark plug and it did the same thing
    www.turbov6camaro.com
    1997 3800 Series II Camaro
    4600 Stall for my ride to the mall :chug:
    7.18 @ 99.77 1/8 -1.8x sixty (current quickest v6 fbod)
    11.23 @ unk 5 1/4 - 7.19 1/8 - 1.83 sixty

    Comment


    • #3
      Can spark plugs just 'crack' on their own? I replaced plugs about 4000 miles ago, and never had a probem until now. And i was really careful to try and not crack any...

      So can they crack on their own?

      Comment


      • #4
        Ok, I just took the car out this morning for a few road tests, and it appears as if the problem has 'worked itself out'.

        It was probably water in a connector or some kind of sensor causing a miss. Either way, car ran great today, so im not going to worry about it unless it happens again.

        Comment


        • #5
          rrgh!

          its back. happened to me today again, a little bit. not as bad as last night, but it still 'missed' a little bit.

          would water between the coil packs cause this possibly? any other ideas?

          i gotta solve this :mad:

          Comment


          • #6
            could be TSP
            or MAF

            you got a OHM meater? test you coils,
            www.turbov6camaro.com
            1997 3800 Series II Camaro
            4600 Stall for my ride to the mall :chug:
            7.18 @ 99.77 1/8 -1.8x sixty (current quickest v6 fbod)
            11.23 @ unk 5 1/4 - 7.19 1/8 - 1.83 sixty

            Comment


            • #7
              try new plugs an see if that fixs it, could be a bad wire too 1 cyclender is all it takes to do that, trust me
              www.turbov6camaro.com
              1997 3800 Series II Camaro
              4600 Stall for my ride to the mall :chug:
              7.18 @ 99.77 1/8 -1.8x sixty (current quickest v6 fbod)
              11.23 @ unk 5 1/4 - 7.19 1/8 - 1.83 sixty

              Comment


              • #8
                1) how can i test my coils with an ohm meter and what am i looking for (i have a friend with a multimeter, its got ohm's on it)

                2) Plugs were changed 4K miles ago. It may be a wire, i didnt change the wires.

                i went to autozone to get them to do the code check, and the bastards said they couldnt, they 'didnt have the personnel'

                Comment


                • #9
                  lol ahh coil ohm i for get but miulti metter will work fine, i can't rember the ohm range try a seach and ill look for it to
                  www.turbov6camaro.com
                  1997 3800 Series II Camaro
                  4600 Stall for my ride to the mall :chug:
                  7.18 @ 99.77 1/8 -1.8x sixty (current quickest v6 fbod)
                  11.23 @ unk 5 1/4 - 7.19 1/8 - 1.83 sixty

                  Comment


                  • #10
                    anyone know how to test coils?

                    Comment


                    • #11
                      Your resistance should be at about 0.50-0.90 ohms. for the primary terminal (underside of the terminals, secondary should be 5000-10,000 ohms, if your getting any less than this you should replace.

                      w/out ohm meter disconnect 1 spark plug boot from coil (MAKE SURE CAR IS OFF!) and turn car on. you should see current, or a spark of electricity going haywire and buzzing if it does this it's good. Then proceed to next coil plug/spark plug wire (do this one by one to see which one is failing. If you see no current or a very weak one on a terminal then there's you're problem.

                      hope this helps bud.
                      ---Niño---<br /><i>95\' silver 5 spd</i>

                      Comment


                      • #12
                        could be plugs, wires, coils, maf sensor...
                        misfires suck!!!
                        mcG<br />aim=endlive<br /><a href=\"http://www.cardomain.com/id/endlive\" target=\"_blank\">97 firebird</a> ~ wrecked

                        Comment


                        • #13
                          trust me could be plugs no matter how long ago u changed them. mine is going through misfire issue right now and one of my plugs was broken and they were practically brand new. maybe 2 months old bosch plats. since the neck of them is ceramic, all it takes is a speed bump or some other hit like that to cause a crack. typically the coil packs arent changed much, so its probably that although thats what i thought on mine and replaced everything possible that would be an obvious problem
                          k&n, flowmaster 80 series,wings west body kit, resonator removed, 180 therm.,carbon fiber,graphics, and a brand new 3.8 engine and tranny.<p><a href=\"http://members.cardomain.com/jbfirebird\" target=\"_blank\">http://members.cardomain.com/jbfirebird</a>

                          Comment


                          • #14
                            Originally posted by pontiac nino:


                            w/out ohm meter disconnect 1 spark plug boot from coil (MAKE SURE CAR IS OFF!) and turn car on. you should see current, or a spark of electricity going haywire and buzzing if it does this it's good.

                            hope this helps bud.
                            when you say "i should see current", what do you mean? i should see sparks from the electrode on the top of the coil?


                            also guys, is there a possibility that if i got water somehow inbetween the coilpack and the base unit during my engine wash, and it is having a hard time drying, that it is this causing the miss?

                            ive read in several other threads that when a miss happens after car warms up, its usually the coils. since this is what is happening, im leaning toward the coils.

                            thanks for all the replies so far, keep em comin, i really appreciate it!

                            Comment


                            • #15
                              this sounds like coil pack or ignition control module, which apparently crack and then corrode (especially if you are using a power washer on your engine, so don't do it). if you end up replacing a coil and it's still misfiring, it's probably the ICM.

                              good luck!

                              Comment

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