91 pathy misfire

[SLEEPER 86]

i have recently replaced the cap,rotor and plugs(.031 gap autolite double platinum),also set the timing to the fourth advance line(of four)which i am assuming is 15*.i did use copper antisieze lube on the plug threads.i am experiencing an intermittent misfire that gets worse as the engine warms up.after pulling wires from the cap one at a time the miss seems to be centered around the #3 cylinder.the fact that the miss gets worse as the engine warms up would lead me to believe that it's timing related,but the relative disappearance of it when i pull the #3 wire makes me think it's the wire?any ideas? thanks in advance for any thoughts/replies!Eric

[SLEEPER 86]

after a closer look there are actually seven marks on the crank pulley white-bare-white-bare-white-bare-white looks like the marks start at 10*after and go to 20* before then.still have the miss though,could this be from dirt under the plugs where they seat in the heads?i had no miss before changing the plugs. Eric

[p00t]

are those the plugs with two electrode arms on them? they are known to foul easy and generally run like garbage... get a set of ngk's. from copper to iridium they will all work MUCH better than your autolites.

[SLEEPER 86]

no p00t,these are single electrode with a fairly small tipped conductor,i did find after removing them that the antisieze lube had loosened a bunch of dirt in the threads the plugs screw into.after cleaning,reinserting,removing,recleaning and reinserting,the threads look pretty good but i still have a persistent miss!i noticed that when i removed the #6 plug(the one nearest the firewall,under the intake,of course!)the washer did not come out with it,and there was oily residue around the base of the plug. could i have missed installing a washer?that's not like me!well after much probing and digging in the blind hole i have yet to produce a washer,but with a mirror and just the right light it really looks like there is one in there!i have tried several ways to remove it,got any ideas? thanks again!Eric

[SLEEPER 86]

update:i replaced the #6 plug With a washer this time!(DOH!)still acting the same.my y pipe has a hole in it so i can clearly hear a miss that is not directly related to any cylinder firing in park.in drive it seems to happen much less often,but there is what seems to be a light exhaust backfire every 8-20 seconds.these seem to be two unrelated problems. i did notice a broken wire coming from what appears to be a condenser attached to the alternator and running to the alternator hot wire tonight,could this be my bug? i appologise for being new to the nissan game! thanks again all!Eric

[NISTECH]

Autolite plugs are notorious for being bad out of the box. swap 1 and 3 spark plugs around and see if the miss follows it. if so the plug is bad, as p00t said use NGK's. Another thing to is look at your dist cap for a "made in" stamp, if it said made in italy you have yet another garbage new part you should replace they too ar notorious for being bad out of the box. The fact this didnt happen till you replaced the parts suggests you got a bogus part.

[SLEEPER 86]

problem was there before the cap swap,i have since swapped another autolite plug,one by one through the whole system,replacing one and swapping in the next,with the same results each time.looks like time to swap the wires out:rolleyes although i did a water spray with no arcs. i did recently did an oil change that required piercing the filter to remove it,could this have affected the o2 sesnor?i didn't see it anywhere below the oil filter,but that doesn't mean it isn't there.i tried to protect the starter with rags,could i have corrupted an electrical flow somewhere?high idle seems fine but the second she idles down i get the miss.less pronounced in drive,but still there.engine has plenty of power under load(at least more than before i did anything).there is still some dirt at the bottom of the spark plug wells that i have not been able to clean yet,are these systems really that ground sensitive? guess i'm reaching here but not sure which way to go first.thanks again! Eric

[NISTECH]

yes they are very ground sensetive. so your saying #3 cyl is still the miss firing cyl? If so you need to check the fuel injector with an ohm meter compare its reading to #1 cyl it should be about the same reading around 14 ohms.