This should probably be under the product review, but I just figured I'd tell this to my familiar people...who knows, maybe your cars will act the same. I've had a set of 6 brand spanking new Bosch Platinum plugs laying around..they're the standard ones, not the +2's or +4's. My car's been acting worse and worse recently, and I've had a suspicion it's the plugs...it's been idling terrible...really rough with a wicked shimmy...and it feels like it's not getting a good spark. So I let the engine cool, grab every socket extension and adapter I've got, and manage to get 5 of the 6 plugs out. The last one is plug #1..can't get the boot off. And the boots with my current set of wires...well, the wires are less than a year old but the boots are rotting out. One tore open on me and the flared grip at the end ripped too. Didn't want to try yanking at the #1 one.. So I'm running on 5 new plugs. To my surprise, when I get the first plug out..it's Bosch Platinum +4! And it's fairly new! No signs of carbon, preignition, detonation, etc..the ceramic is just a little scorched around the top. But I get the new plugs in, expecting no difference since what I just pulled were premium plugs..guess what? My idle clears up about 70% right off the bat..car runs way smoother now. Throttle response is more linear too. Car still runs a little off, but I'm getting that last plug soon and I just have to get a timing light so I can get the cap and rotor in and set timing...hpefully that'll clear it up. I figured I'd give you guys a heads up that, at least on my car, it does NOT like the +4's at all. Avoid them! That and they cost a fortune..around $5 each.

We already knew that....

I've heard people say they're not worth the extra money..but I've never heard anyone say they run like sh*t.. I mean, there's no reason these should have been running bad...I'll see if I can't get a photo of them later. Cam doesnt like the dark...

arent you supposed to do something with the timing if you put in bosches? I cant remember if its advance or retard, but I think you are supposed to because the are so efficiant

I dunno...but since our cars can handle an extra 2 degrees of timing, probably more, I would assume if the plugs were more efficient you'd have to retard the timing..but I'm sure the stock 10 degrees would be fine. I haven't checked mine yet. When I swap the cap and rotor I'm gonna try running 12 degrees for the extra throttle response.

Even the stock ignition in our cars is too hot for platinum plugs. the electrode will not hold up. They will work great for probably about 2 weeks with normal use and then its down hill from there... fast.

Try good ol' Autolite plugs. They have the largest electrode and last forever in the hottest ignitions.

I have had huge ignition problems in the past so I took no chances and got MSD 8.5mm wires, ACCEL module, cap and rotor, 300+ multi spark unit and of course, the Bosch Platnum +4. I only use them to make sure that my car always produces a spark under varying conditions. AC rapid fires are just as good. The +4s are expensive. If I did not have so many ignition problems in the past I would not use them. I can't tell you if they made a difference because I got all that ignition stuff at one time and installed it together.

I have heard that they can cause stress fractures.
they run tooo hot.
Blah, balh blah blah.


It has been know for awhile that we shoudn't use them


I'm a Rapid Fire kinda guy

you know people say that about every car, Dont know how many times Ive heard that about any car. Just a given that at the factory that bugger the timing and other setting to make the EPA happy, not you.

KJRockz, yes they do run hot. I don't think it is hot enough to cause damage though. I probably won't get them again because it seems redundant to have them since I upgraded every ignition component. I want the best spark possible though, so I will most likely use AC rapid fires, after all, they are GM approved parts. I had mine for over a year and I have not hat a single problem with them.

Wish I would've known this before I shoved some platinums right back in......... Oh well. I'll keep em til they get real bad and throw rapidfires in. By the way..I just have to ask..is it normal to have rust in the spark plug holes? Just something I noticed while I was taking them out...there was some rust in there. Not real bad, but pretty orange-ish.

It's not good, but if it is such a small amount, I wouldn't worry about it, just clean it up a bit. If the rust is in the threads, your next spark plug change may make the threads stripped.

ok..thanks.. It was more of a powder than chunks of rust. I just have a ...."thing" about rust..lol. I see specks on my car, it drives me crazy. I see rust forming on my supposedly rust resistant tips...I go crazy. I see rust in where my spark plugs go..lol..well, I get more worried than crazy.

put some anti-seize on the plug threads. while not really needed for iron heads, it could help keep moisture/corrosion out

Rapid fires all the way!

That is always a good idea for installing plug heads.




I would recomend these over any other the Bosch platnum +4s, even though I really like them because the flame has four choices to make a spark from.


The best plugs you can get for the street are iridium plugs. The tips are almost needle like and they actually produce a small amount of bhp by themselves. They cost $10 a piece!

$10 a piece really isn't bad for iridium plugs... Those things are crazy..the spark they produce is so white hot and I hear they last like FOREVER...the iridium has a really really high melting point..I think they use it in the space shuttle for something, maybe the heat tiles... Of course we'd never really utilize iridium plugs..except as far as the plugs are concerned, they'd fire beautifully for years and years I'm sure.. In the long run, who knows, they might even be worth it...depends on how long they keep good.

Iridium plugs are a new one on me. Who makes them?

I saw them in an import magazine, the plugs are pretty new for most cars.

Last time I heard, they were being custom manufactured by some guy out west I think.... Dev, a major import manufacturer picked them up? Good deal if they did...I'm sure they were outrageously expensive from "some guy out west"...

All I know is that they were $10 a piece. If I find the add I will post it.

Good deal...... Wonder how long they last, or their heat range....