Hi Again,

So close here after checking through the lists and then getting a Bosch Factory O2 Sensor (eBay lag for time here).

Sticker has expired and I thought the O2 sensor would do it, no luck (my last test for the 19 year old tank)

Levels after the four load tests are;

Test 1 Test 2 Test 3 Test 4
HC ppm 93 46 49 88
CO% .14 .05 .05 .13
NO ppm 1986 1377 1318 1109

The new cut-off for NO in Ontario for this year is 1088, so I am over by ONLY 21 ppm. Well below the older limit of 1415 (in 2001) and 1252 (in 2003) a few years back.

After test one I did re-set the timing to about 11BTDC (I cannot turn the distributor any further to get this any lower?)

After test two I checked hoses for cracks and leaks, and ran some 'Guarenteed to Pass' cleaner through. Well didn't pass.

After test three I changed the O2 sensor (needed Garage help here) and even put in 1 litre of Methyl Hydrate on the 1/2 Tank of gas (wink, wink tip from the garage O2 helper).

What next? The CAT is old, but I suspect fixing the cause is better than treating the symptom.

Any tips greatly appreciated ;>)

Greg