996 3.6 misfiring

[5STM5]

On a run yesterday and had to head home early. I was sitting around 3k rpm and 55 mph when I felt something rough, there were no warning lights so I thought I may have driven over something. A short time later it happened again, this time with an Engine Warning alarm and the car was running really roughly.
I pulled over and switched the engine off, restarted it with no warning lights but when I accelerated the misfiring started again with a warning alarm. One thing I noticed was the Oil Pressure gauge fluctuated slightly when it was misfiring, it’s usually very steady.
I nursed the car home around 15 Miles.
Could this be a fuel grade problem, or spark plugs? Or can I be looking at something a bit more serious? I had the water pump replaced recently, is there anything in that area that could have been disturbed?

[5STM5]

I've just driven it up and down my driveway, definitely still misfiring but no alarms now. Fingers crossed its something simple like plugs or coil packs.

[5STM5]

Surprisingly fault codes showed 3 cylinders misfiring, 2-4-6. Going for the plugs and coil packs first, all 6, hopefully that will sort it.

[5STM5]

As suggested the coil packs were the problem. Car is running great again.