2001 TJ 4 sp non tip.
I have noticed a change in my exhaust pipe over the last month or so...
Rather than the usual black, its a definite brown.
I've recently had oxy sensor changed, so it might be that...as my fuel economy has picked up about .5L/100km.... and i mostly do Highway work with a usual 7.9 to 8.1 average @ 100kph.:dancin:

But could it have something to do with the fuel? My suspicions were raised when i heard an old timer down here in Tas talking about winter blend fuel. Having worked on aircraft for 15 odd years, i have never heard of such a thing in that industry, and wondered if there is any creedence to the story, or its just a coincidence.
Anyone else noticing brown in their pipe? Would particularly like to hear from regional dwellers as well as big smoke folk..

You probably are running your car much more efficiently than you used to. If it gets properly warmed up, it will run cleaner and use less fuel. This could be the cause for the brown deposits in the exhaust pipe. The winter mix you refer to is diesel - detergent is added to minimise wax buildup in the fuel (this clogs up fuel lines and also any leakage into the sump can cause the sump oil to freeze up and thereby starve the engine of lube oil) - nasty.

Black = soot ie: over fueled, Clear = no deposits so the water that condenses in winter will rust the pipes a bit = Brown, sounds like the oxy sensor has fixed your cars efficiency.

There is certainly winter blend diesel - haven't heard of petrol though - diesel can go gooey at below freezing, not sure what the freezing point of petrol is but I assume Australia doesn't get there....

Horay for AMEs - Know anyone needing an apprentice (I've finished my schooling)?

Anyway, Do you have ethanol blended fuels in TAS?