Outer Limits 4x4 Board

I just pulled these plugs out of my 99 GU 4.5 petrol/gas. They have done just under 20,000km. The number in the pics is the cylinder it came from.

What do the all the different burn marks/colours mean? Are these rich/lean mixtures, burning oil etc?

No 1 looks spot on, the others look a little on the lean side.

No 5 looks like it's been getting hot, you might need to go one heat range colder plugs

is it just the pics or those spark plug gaps look a little on the big side ?

As mentioned, 1 is spot on.. The rest look a little lean. Gaps look fine. Maybe could be closed a little for gas but they look about right for the standard petrol application.

Cheers fellas. Those pics in that link are a bit dodgy...

The gaps were at 1.1mm, The new set I put in I closed to 1.0mm. The old ones were a colder heat range (6 instead of 5) as are the new ones.

Good to know they aren't too bad.

I spent the extra and put platinums in mine .. the rear two are a pita to change in my opinion. Cost 3 times more last 5-6 times longer can run a bigger gap with less strain on the ignition system etc etc ..

The 1st one looks great the others look OK I certaily would not be staying up at night worrying about em.