Thread: multiple misfires

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  1. #1 multiple misfires 
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    hi guys,i have a couple issues with my 2000 gtp,i have the following mods-3.4 pulley,dhp pcm,thrasher cai,borla exhaust,hiflocat,tog headers,msd coils,taylor wires........now my gtp only has 35000 miles and has never given me any issues till now..........while driving the other day the car started to misfire pretty bad that it threw a multi misfire code........the first thing i did was change plugs,ac 41-101 are the replacement for the 41-921.....still had the misfires......so i put back stock coils.......car started to pull much better at take off,but still misfiring under heavy load,,although not as bad as with the msd coils.....soooo im thinkin the coils were the fix,but by changing the plugs maybe i did somethimg wrong? wrong plugs?bad gap? wires? keep in mind though the car only has 35000 miles........so im lost about these misfires..second issue is the sc........started makin rattling noise.so i changed coupler,noise still there.so im thinking its the needle bearings...i see rebuild kits all over the net,how hard is it to rebuild using one of these kits? thanks in advance guys....ron
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  2. #2 Re: multiple misfires 
    GrandPrix Junkie machinegunsquid's Avatar
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    Kinda sounds like what was up with my car. I had MSD coils, and one split down the middle between the contacts. The car idle'd fine, but under load it was misfiring like all hell. I changed plugs, and it idled like hell. Once I changed out back to stock coils, it ran quite a bit better, but still misfired some under load.

    Turns out that the plugs were bad (brand new ones) Once I put in a set of properly gapped Autolite 104's, I had no problems.

    As far as the S/C rebuild, I have no idea how easy it is to do.

    "**** bills. You can live in your car but you can't race your house" -dsmuts
    Want her to stop when she's not looking karate chop her in her crotch that should quiet her for a bit or at the very least put a smile on your face -REDCOMPG
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  3. #3 Re: multiple misfires 
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    hmmm....before i changed the coils,i did change the plugs.....i put ac 41-101.....im thinking maybe the plugs were gapped wrong,as i didnt check,i assumed they were pre gapped....or maybe i messed up putting them in? i swapped back to the msd coils just to compare and it misfired more off the line than with the new stock ones i got.....i got some ngk pluggs today i guess i will give those a try.......
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  4. #4 Re: multiple misfires 
    resident snitch gtpinsc's Avatar
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    could be fuel related misfire... if it doesnt fix with new plugs, try a new fuel filter and run a can of seafoam through the tank.

    02 GTP with mods 05 GP for DD
    Quote Originally Posted by SuperSport View Post
    The majority of the people here are potheads who want to buy good condition parts at junkyard prices.
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  5. #5 Re: multiple misfires 
    GTP Level Member 01gpgt01's Avatar
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    Quote Originally Posted by rsookar View Post
    hmmm....before i changed the coils,i did change the plugs.....i put ac 41-101.....im thinking maybe the plugs were gapped wrong,as i didnt check,i assumed they were pre gapped....or maybe i messed up putting them in? i swapped back to the msd coils just to compare and it misfired more off the line than with the new stock ones i got.....i got some ngk pluggs today i guess i will give those a try.......
    plugs are probobly gapped to .035 get Autolite 605 or NGK TR55 and gap to .054 or so
    2001 GT. A few here and there mods http://www.streetfire.net/video/2001...ynp_208097.htm

    2009 Hummer H3 Solar flare premium
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  6. #6 Re: multiple misfires 
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    TR55's come gapped at .059 unless they were hit in shipping.

    needle bearings involve tapping the hole behind the bearings and then putting a grease fitting in there and pressing them out with grease.

    Then you press the new bearings in.

    If you find someone who can do it.... which will be tough, it should only be $20. Thats all I paid.

    + the bearings obviously.
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  7. #7 Re: multiple misfires 
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    update guys.........i figured the original problem were the coils,but before i changed the coils i changed the plugs,i got the ac 41-101,i assumed they were pregapped and put out them in,misfires was still there,than i changed coils,car ran much better,but misfire was still there at wot,sooooo today i changed the plugs again to the ngk tr55"s and gapped to .059............misfires gone!!!!!!! yah!!! as far as the sc,i got one offf ebay for 225...going pick it up tonite,hopefully its in working condition...........thanks guys for all your advice!!!!!!!!
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