The only ones that seem to be working for people are the HT0's. Stock plugs are HT1. HT stands for half thread which is the funky design used on our cars. The number is for heat range. A 0 plug is one range colder than stock. Gapping is critical and takes a special tool. IIRC KB recommends a .030" gap, best to check with them as to what they recommend. I've used FRPP HT0's gapped at .032". That's Whipples recommendation and they are available pre-gapped.

I have no idea what a dealer will charge. Shouldn't be a whole lot.

Something else you could do is to switch your #8 cop with another and see if the misfire changes cylinders. If so then it's a bad coil on plug (cop).

 

Bruce, are these what you use/would reccomend I look into?

http://www.fordracingparts.com/parts...KeyField=10576

 

No, those are the new style. As long as your heads are original 06's you will need these: http://www.fordracingparts.com/parts...tKeyField=8978

Turns out HT stands for high thread.

 

be careful with the 08 and older version plugs, I remember reading the TSB about the risk of them seizing and breaking in the head

even that being said, the plugs are easy to get to and I wouldn't pay the dealer to swap them out personally.

 

Well, the check engine light went off today, just as I was on my way to the local speed shop to have them check it out... Is this normal? Does this mean that I am "in the clear"? When I took it to my local speed shop, they highly reccomend I do a compression test and possibly a leakdown test...If i had a bad cylinder, wouldn't I have more symptoms than I have now? We did change the COP from the number 8 cylinder to the number 5 cylinder, so if I throw another code on the number 8 cylinder I think I have a bigger problem...what do you guys think?

 

Well like fresh said I have had problems with mine misfireing since about two weeks after I put on the blower. I use to misfire atleast once a week. But now I can go a month or so with out a problem. I have had a leak test done and ran on a dyon and they couldent find anything wrong with it. I've spent a lot of time on the phone with KB and they have ran out ideas.

So I'm not sure if it's been said already but are you running the brisk plugs they recomend? If so try putting stock ones in, they told me it's fine running the stock ones and my car runs better with out the brisks. Also what are your plugs gaped at?

 

Thanks for your input black n blown, i was hoping you would chime in...So I take you have no symptoms either? Is it always the same cylinder even if you change the COP? I am not running brisk plugs, and to be honest I am not sure what they are. I was browsing the original owners posts from awhile back on another mustang forum, and it looks like he was running the HT0's I believe, and I think gapped at .045? Isnt that what KB used to reccomend I believe? I talked to KB today, and he did mention the brisk plugs, and gave me the right model number (ors14v or something? I have it written down here somewhere)...KB also mentioned, that if you are granny shiftin along (really babyin the car) That can foul out the plugs sooner at times as well. Well, it just so happened, the code came up when my dad was just drivin like a grandma, low rpms etc...so who knows. What is the worst case scenario with my situation?

 

Yeah it never changes, I've moved COPs around and the plugs. Yeah they say start at .045 but I think I'm at .035 right now I'll cheack in the morning for you. They had told me to try the smaller gap and it had hepled some what. And it won't hurt anything with the smaller gap. I'm sure that babying would cause that. When mine tendes too miss is if I'm in like 4th gear and hold it a 4000 RPMs then go WOT it will start missing. And I also get codes for misfire on start up. I'm not sure if you have gotten that one

 

Yep, I have gotten the start up missfire as well. Although I don't throw a check engine light, I just had it hooked up at a speed shop around here, and they told me I had missfire on start up, so i was kinda worried about it. so you said it DOES stay in the same cylinder regardless?

 

FYI the sell the HTO's pre-gapped. You dont want crew of gapping those things, there a PITA. I bought a pre-gapped set from whipple.