Consistent misfire on Cylinder 5 causes?
 

I have a 99 base USA spec car. I have had the car 5 years. I probably put 1500 miles on per year. I am getting a consistent misfire on cylinder 5. Consistent being the last 2 days. Last year I replaced the coil packs with with BERU upgraded mounting units. About 3-4 years ago I replaced the spark plugs and tubes. I am not sure I think I used NGK plugs. I change the oil and replace air filter every spring. What could be causing the misfire? I ordered another coil pack and was going to replace the #5 spark plug just to be on the safe side. I am thinking it might be the wiring to the coil pack. I found plug with wiring for $35. Anyone have any ideas what it could be? besides coil, plug, wiring?

do you have an aftermarket intake or have you done work in that area of the engine? the wiring to the #5 fuel injector is exposed to damage where it plugs into the injector.

Intake is stock. Last winter I did a complete suspension overhaul. That is most recent work. I might swap coilpack with #4 and replace spark plug to see if that makes a difference

Swapping the plug and coil is a good easy test. A compression check will help eliminate (or suggest) some possibilities. Compression testers are cheap and not too hard to do the check. Possibly the injector on 5. I've never had a bad injector, but i expect it can be swapped with another cylinder to check if you don't want to take them all to a shop.

I’d swap coil packs to see if the misfire follows. If not, do the same with plugs, then injectors.

I swapped coilpack on cyl 4 & 5 and went for a long ride. No misfire so I am thinking the plug was loose on cyl 5. Hopefully non issue!