And a waste of money, too!

 

Champion or NGK copper plugs and be done.

 

Forget the Champions. LOL!!

 

So much dislike for champion plugs. Lol, just curious, but why the dislike?

 

NGKs have always served me well. Champion has been known to recommend the wrong plug for certain applications.

 

I used them as well in many applications, but i just had alot of people recommend champion. Regardless of brand i always check gap and spark.

 

That too! It's the old age setting in. LOL

 

"Bosch are gimmicky crap." Kind of curious what the gimmick aspect is -- they just look like spark plugs to me.

In any event I respectfully suggest that you don't know what you are talking about in this case. Of course there has to be one Supreme Being on every forum and if there were ever a question about this one...

Or, perhaps I have the one XJ 4.0 in the whole bloody world that has some magical affinity for platinum plugs. Kind of fun to disrupt the smug superiority of the experts now and then, but truth be told, I really and truly don't care whether you believe me or not. As I have said before, I gave the coppers a two year chance to provide a completely fair comparison and they were not even close. Others have had a different experience and I don't question that.

 

My only question the remains is, why does it say the correct spark plug is the RC12ECC under the hood and It didn't work?

 

i got Autolite platinum# AP985 in now..i did have Bosch platium +4

 

To a lot of people, platinum plugs are just expensive and pointless. I've tried them in various engines ranging from the 60's up and in 2 and 4 stroke motorcycle engines. They supposedly increase gas mileage, horsepower, blah, blah, blah. I've never seen them follow through with any of those claims. Thus the branding, gimmicky crap. That and Bosch plugs are the only spark plugs I've ever tried that have actually made my engine run worse. Of course this is my own opinion based on my own experiences and doesn't represent opinions or experiences of others. Personally NGK will always be my first choice in spark plugs because they've let me down. And whenever I can't get NGK plugs Champions will always suffice.

 

cruiser is a well respected voice on this forum, and I have seen him help TONS of people in my short time here.

That being said, it is a known, tried and true tested fact, that copper plugs run extremely well in the 4.0 engines IN MOST CASES.

I am sure that if you run a platinum plug in a 4.0, it will most likely run fine.

BOSCH gets a crappy rep from the platinum +4 days.. those are a known gimmick..

It is just the gold standard to give the advice that is concrete proven to be a reliable replacement part IN MOST CASES.

 

Same here. Made my Alfa Romeo run worse, along with my buddy's Honda Civic.

When they first came out, we put my Datsun 260Z on the dyno at the local college. Always ran NGKs.

Put brand new Champions in and did a pull. I was hitting 6000 RPM in 4th gear.
Recorded the numbers.

Swapped to Bosch Platinums and did the run again. I LOST 28 horsepower to the rear wheels.

Yep, those are some great plugs.

 

Why did you change?

 

Hey I bought these spark plugs and still the same issue of misfiring on all cylinders, checked the gap and when I compared the piece where you check the gap are two completely different sizes. This is the only thing that comes to mind about why it misfires, but please any help is wanted