1995 Suzuki Vitara cut out while driving.

G16B engine - the customer said it died on them - they had a fiddle with it first and I found the distributor was 180 degrees out and
rotation was backwards so every now and then it would start and run on two cylinders. I have it running again but every now and then it starts misfiring - on cylinder 3. I quickly swapped spark plugs over (should fit new) and it's still cylinder 3 which is getting good spark when it happens.
All that is left is the injector, which is getting pulsed when it's misfiring. I'm just wondering about my vacuum gauge reading - it looks pretty high
and drops to 22 when there is the misfire - how do I tell, without swapping injectors around, if it's the injector or a sticking valve? I will upload a video as well. This is at 2000 rpm, it is slightly less at idle, air filter removed to make sure.

Here's the video showing it running normally and with the misfire. I imagine since the gauge doesn't bounce a lot
it is most likely the injector?

Disable the ignition, or fuel, and give it a good, long crank. Listen to the starter. Does it sound nice and smooth? Or, does it have a distinct pattern, or rhythm?

or just current ramp the injectors and look for either a missing ramp or a shorted one

The trouble is that the fault is intermittent, it may run well for a few minutes before it starts misfiring.
A compression test shows it as being good - but then a sticking valve isn't always stuck....

In my experience sticking valves tend to stick from a cold start and may free when the engine reaches working temperature. Sometimes injector or intake cleaner will free a sticking valve

However a bad injector may work fine from a cold start but develop an open when it gets warm. So an injector problem looks more likely.
Without a scope you *****might**** be able to hear (ie not hear) an injector not opening with a stephoscope or stout screw driver held to the injector body but this can be difficult because of the sounds of the other injectors echo through the fuel rail.

+1 to Andy

In that Suzuki engine i think is easy to "listen" the injectors also ...

Get your needle stethosope and try listen all the injectors as the engine runs ok, you should listen a "deep - click clack" when the injector working

and then listen them again when the misfire starts, if there is no "click clack" noise then you have to focus on pulse or 12V or injector itself ...

I found, with that "old fashion way", a very intermitted injector cut off for 1-2 sec in a Citroen last week by that way.

Thanks guys, I had our mechanics listening to it Friday afternoon, one of them told me a sticking valve is very unlikely so I do agree it is most likely an injector issue.