Hi,

Looking for some info on which type of Spark Plug should I be using in my cossie and what gap they should be.
I have a 1992 sierra 4x4, running 330bhp, stage 3 chip. I only bought it a couple of weeks ago and decided to get a service done. But I think he may have put different plugs in it, not sure. The mechanic doesn't know why it's backfiring, checked all the usual, more of a thumping sound through the exhaust now and then, sometimes loud! So I just want to eliminate the plugs. Any help would be great as it's annoying the hell out of me.

 

get yourself down to your nearest Ford dealer and get some 071s - finis code 1120834. set of 4 for about Ł12

 

I used the 071's , found they were crap changed to new AGPR12PP8, what a difference, way better.
The thumping sound is probably hunting, ie missing a beat, have you got decent leads, and coil(group a) ?
tabetha