Knock sensor location needed

We should start with checking for codes. Here is some guides that will help with this:

https://www.2carpros.com/articles/how-a-knock-sensor-works

https://www.2carpros.com/articles/suzuki-code-retrieval-and-definitions-1986-1995

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

It is unlikely that this is a knock sensor as that will only advance or retard the timing if the engine was knocking or detonating but if it is the sensor then it will have a code.

If it is running poorly and the timing was just set, I would suggest with checking the compression to ensure the timing is correct.

https://www.2carpros.com/articles/how-to-test-engine-compression

If the timing is off then a valve will be opening too early or late and it should affect the compression which will cause a poor running condition.

Then we need to check for vacuum leaks and check the vacuum of the engine/intake valves with a gauge.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know what questions you have. Thanks