Car had rough idle

I suspect we have a separate issue then the rough idle if this was fixed by adjusting the timing.

So that means we need to start with checking for a vacuum leak. Normally this would cause a rough idle as well but if you were able to adjust the timing enough to smooth this out, we could still have a vacuum leak.

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

If there are no vacuum leaks then we need find out what the timing was adjusted too.

If they retarded the timing too far then that can cause fuel mileage issues but this would mean we most likely have another issue that the timing is just hiding now.

So let's use the info below to check the timing and see where it is set and go from there. Thanks