[Speed]

Ok, here I go again... About a montha ago, I changed my factory Motorcrafts to Champions. A slight miss developed at every cold start, that would smooth out once warmed up. i pulled them, rechecked gap, torqued them to spec. they were ok or a while, util last sunday i got a p306 code, misfire #6. Seeing I just changed plugs, i suspected a failing coil. Bought a coil at local NAPA installed it , no code, but still have miss at cold start, which smooths out after a couple of minutes. Now Ive heard both sides of the argument that some people say stay away from champions, and go with HT1s. Im lightly modded with a CAI and 91 octane tune. Should I go with the Autolite HT1 (2 piece plug again?)? One more thing .. how are the cylinders numbered. I cant find a chart in the shop manual. Haynes shows a diagram but im confused which is the front or rear of engine for the purpose of reference. Any advice would be appreciated, thanks

[angelo07stang]

I run champion plugs and havent had a problem yet they been pretty good.

[smokinbones]

Haynes shows a diagram but im confused which is the front or rear of engine for the purpose of reference.

Left side front to back #1 in the haynes manual, then #2 & #3
Right side front to back #4, #5 & #6

[gmantheman]

I had Autolites installed about 8-10K miles ago. No complaints so far. I haven't read any complaints about the Autolites, yet I have read a few about the Champions.

[stlwagon]

here you go.......

[Speed]

Thanks,STL,Now I know Im zeroing in on the correct cylinder

[stlwagon]

You could have a defective plug or even a cracked insulator.

[Speed]

found #6 plug center electrode gone! spark had to jump a long way to the outer electrode! Seeing that they are very fragile, maybe I accidently cracked it while checking the gap. Bought a new Champion 7989 fired it up, and she runs as smooth as silk now! Im up for my 1st emissions test now and I didnt want any misfire codes popping up! One piece plugs, smooth idle, and no fault codes... Amen!!

[stlwagon]

Originally Posted by Speed

found #6 plug center electrode gone! spark had to jump a long way to the outer electrode! Seeing that they are very fragile, maybe I accidently cracked it while checking the gap. Bought a new Champion 7989 fired it up, and she runs as smooth as silk now! Im up for my 1st emissions test now and I didnt want any misfire codes popping up! One piece plugs, smooth idle, and no fault codes... Amen!!

Good deal.... I figured it was probably the plug.