My car hates autolite plugs...why?

[dmahlikGT]

Ok so some months ago i did a tuneup and put in autolite 605 plugs in.After i did everything and started up the car took it for a run and it just misfired couldnt even do a nice pull. So i took them out and made sure they were gapped properly,which i adjusted them at a .055 ish gap. Did another run and bam still misfiring under part-full throttle. Ok threw stockers back on. Fast forward to today and I have had these AL104s sitting so i figured now would be an ok time to install since im throwing other things on it. Gapped them at .050 before i put them in. Did everything i needed to do, went for a run and same exact issue the car misfires at part-full throttle smh. So i said screw it and waited for the car to cool and threw stockers back on and car pulls nicely again. Can I not run anything less than stock plugs or better yet Autolite plugs,any ideas?

[dmahlikGT]

But i see plenty of people running autolite this,autolite that and no problems for them.I dont get it,these plugs seem to be a waste.

[Fivefingerdeathpunch]

You never said which cylinders were misfiring.

You are using copper cores right?

Platinum plugs is general hate our waste spark ignition system, eats them.

[dmahlikGT]

I have no way to scan to see which cylinder it is.And yea both sets are copper core,says it right on the box. Its just weird they both make my car misfire im stumped guess ill be staying on stocks for now.

[REDCRAPGP]

Could be just a bad plug. I've had that happen before with a few packs I've bought. One plus would cause misfires swapped in a new one..misfires gone. Just the luck of the draw but at $2 a piece I don't complain I buy enough to last awhile anyways.

[dmahlikGT]

Pretty odd for it to be 2 different sets of grade plugs from 2 different places both causing the same issue. I guess ill buy NGKs soon and see if that works.

[dmahlikGT]

Well i did some digging and careful inspection and well what do you know one AL605 plug and one AL104 have 2 hairline cracks along the outside of the white part. The 605 plug actually has more of the hairline cracks while the 104 plug has 2 deep cracks in it. Im guessing this would be my issue correct? Dont know how i oversaw those.

[Utter99]

Sounds like some bad luck ^

[dmahlikGT]

Yea you tellin me.I dont know how they got like that though,maybe install error on my part,overtighten? I have no idea but ill just buy one of each tomorrow and try again carefully.

[Sandman]

Yup that's your issue, a new plug will fix the issue.

[REDCRAPGP]

Bingo cracked plus will cause that thankfully they're dirt cheap anyways.

[Scottydoggs]

does the socket your using have a rubber insert to hold the plug tight in the socket, if not that could be why the plugs broke.

[SlowNA06]

For response 14, I would like to point out the obvious:

If the engine was not knocking on stock heat range, why would you change heat range?

[dmahlikGT]

does the socket your using have a rubber insert to hold the plug tight in the socket, if not that could be why the plugs broke.

Hmm didnt remember seeing one. But why are all my other plugs fine? One thing to note,I always have a hard time with #6 plug and maybe all the fumbling and tightening causes the plugs to crack back there.

[Scottydoggs]

cylinder 4 middle back is wedged by the o2 sensor, if the socket cocks on the plug, it snaps it.

ive done it before myself on cars with headers that were a tight fit, good old cyl #8 with a/c on a big block chevy= 3 universals and extensions lol and a snapped plug every now and then.

since then i always use spark plug sockets. the rubber inside keeps the plug tight to the socket, and it cant fall out of the socket either.


if you dropped a plug, that could have cracked it too, but then you would have also needed to drop one from the other set of plugs as well maybe?

spark plug socket.

[txslow6]

That's cylinder 6 that's wedged by the O2 sensor. I've cracked ones on that cylinder myself.

[dmahlikGT]

Yea txs im thinking thats whats happening but then again my stock plugs have been fine with the 99million swaps ive done since then. Tomoroow is the moment of truth, bought one AL104 plug and rechecked them all just to make sure no other cracks.Will reinstall carefully tomorrow and see if I can finally get fresh autolite plugs in without misfiring.

[dmahlikGT]

Success! Went out about an hour ago and changed the plugs to AL104's. Carefully did the front bank plugs first then made my way to the rear and was even more careful. #6 cylinder tried me again getting in the new plug but i found myself an easier way to get the plug in without too much hassle. Fired up the car let it run for a few minutes,revved no misfire. Then went for a drive starting off easy then part-full throttle and no misfire! Car seems to feel healthier now,thanks for all the help guys.

[txslow6]

Glad to hear it. Sounds like it was more than likely operator install error. Happens to the best of us. Now buy more mods and be happy.

[dmahlikGT]

Pulley drop and tune next!