Hi all.
81 Scirocco has 255K+ miles on original motor. Wife drove it less than 3400 miles during the last 2 years. It seemed to be running good, so I just drove it to the smog tester without any interim hard driving. It failed. HC was 90/110ppm at 15/25mph 2 years ago but is now 190/150 (max is 162/132). CO has risen slightly, NO has dropped slightly, but both less than 50% max.CATC and Oxy switch about 4 years old. Air filter old but well within mileage limit. The engine uses about 1.5qt oil per 500mi (almost all short trips) and is due for oil change. Wonder which of the following might bring HC into spec.
- switching from the usual Castrol GTX 20-50W to a full synth 20-50W, then taking a long drive
- new air filter
- new spark plugs
- new CATC (only 10K mi but I'm told high oil consumption ruins catalysts. Is it possible to clean a CATC subjected to excess oil?)
Thanks.
nf