I can't locate an oxygen senzor on Jetta 1987. Any idea??

look on the downpipe behind the engine

I did look all over. I didn't see anything. Somebody said, that would be enough, just drill the hole into the front of catalic convertor a place the sensor there. The another problem is, where to run the wire from that sensor.

I can't help you because my car is an '88 Cabbie. However, if you don't have one already, buy a Bentley service manual for your car. I can't get along without my Bentley, it has good info for just about everything in or on my car.

Where exactly in the world was the 1987 Jetta sold?

TBerk

My point was to work on the fact that some place in the world it might have had A. a different downpipe/manifold and/or it might not have come with a an O2 sensor at all.

TBerk

O2 sensors on 80s VWs are usually found at the first available point where the exhaust from all 4 cylinders would mix. In the case of a single downpipe car, it'd be near where the manifold outputs. In the case of a dual downpipe car, the exhausts don't fully merge until the start of the cat so that's where you'd find it.

The A2s were sold overseas (and in Canada for a little while) with a 1.8

90hp 'MZ' engine. It had no cat and took leaded fuel. I don't know much about this engine apart from that except that it wouldn't surprise me if it didn't have an OXS.