'99 626 Running very rough

I have a '99 626 w/ a 2.0 4 cyl. The check engine light came on one day, this was shortly after my wife got gas. The engine started running rough. I went to autozone and they read the code as a misfire in cylinder one. I replaced the injector in cylinder one. I did a tuneup on it changing the spark plugs, wires, and fuel filter. This didn't help so I was told that the intake gasket. That didn't help. The engine seems to be getting worse. Backfiring through the intake during acceleration. Sounds and feels like it is running on about two cylinders when accelerating moderate to fast.

start simple, do a compression check on all four cylinders. they should all be with-in 20lbs. of each other. example, #1 160 lbs. #2 148 lbs. #3 152lbs. #4 155 lbs. Should you find one, or two a lot lower like 40 lbs. or even 0 lbs. Then you know if you need major engine repair. Hope this helps. Later Mark.

My problem was something very simple. I replaced the plug wires twice and commonly ruled that out. After taking everything appart again, I noticed a carbon track on the number one cylinder plug. Replacing the plug and wires fixed it. Use Belden wires.

done