Spark plugs - wtf?!

[Laursdahl]

Hey..

Just bought my first Rx7 one week ago...

And i wanted to change Oil + sparks just to be sure its ok.

But when i replaced the plugs i noticed that the Top mount sparks was B9 NGK\'s (like the one i have bought for it) But at the buttom theres was a set of B7?!  i dont think this is normal or is there something i dont know?

-Lars

[Hayward North]

From stock mazda use 7s for the leading and 9s for the trailing .
or is that the other way round ?
Anyway just replace them all with 9s

[m1tch]

I guess it depends on the state of tune of the engine as to what heat range you should have the plugs, what plug combo is everyone running on here as a matter of interest?

[Laursdahl]

Oh and another question...

The Engine is kinda running wierd.. When you are at cuising around and almost not hitting the gas pedal. i makes a wierd sound.. I can only compare it to when a 2 stroke engine begins to run like a 4 stroke.. It stops quickly when i push a little harder on the pedal.. Any suggestions? IT only comes when im almost not touching the pedal.

[peterwolds]

I guess it depends on the state of tune of the engine as to what heat range you should have the plugs, what plug combo is everyone running on here as a matter of interest?

9\'s all round same when got the car as standard now 305 rwhp

[Alison]

I guess it depends on the state of tune of the engine as to what heat range you should have the plugs, what plug combo is everyone running on here as a matter of interest?

9\'s all round too, was under the impression that would be fiiineee....

[Matt_K]

7\'s & 9\'s here, no issues.

[marcusd666]

9s all round here to fitted by pip at a full service.

[RemarkLima]

Oh and another question...

The Engine is kinda running wierd.. When you are at cuising around and almost not hitting the gas pedal. i makes a wierd sound.. I can only compare it to when a 2 stroke engine begins to run like a 4 stroke.. It stops quickly when i push a little harder on the pedal.. Any suggestions? IT only comes when im almost not touching the pedal.

Are you sure it\'s not the airpump, which runs under 3000 rpm IIRC. It\'s a belt driven pump which puts air into the cat to stop it getting too hot and helps with emissions.