I thought the same thing. I checked the voltage on both the injector and coil wires. Both are good there. I also replaced all four spark plugs and have even swapped spark plugs coils and even injectors. The code is always specific to cylinder 1(OBD2 code 301). Checked the wiring on the coil and injector and the voltages look good. But cylinder 1 just refuses to fire. If I unplug from the coil on cylinder one there is no change in the engine's sound. It's simply running on 3 cyinders. At first I thought that the cylinder 1 was working after clearing the engine code and starting it but that isn't correct. I had some else start the car and immediately unplugged the coil on cylinder 1 to see if the engine noise would change. It does not. Only after running for about 30-40 seconds does the engine start to run rough.(That is also exactly when the engine light comes) There seems to be something in the diagnostics. I even pulled the coil out, put a plug in it while it was out of the engine to see if it sparks and it does. Is there some way to check air flow for that cylinder. Maybe not enough oxygen to fire? Also when putting a coil in, the rubber at the neck is really tight going over the plug. Maybe it's just not making contact with the plug?

 

If the coil isn't pushed down completely, you'll see that it's higher compared to the others. And the coil & plug work outside of the engine.

Compression test?

 

Yea, I have been wondering about the brand of coil that I used. Was different than the old ones(they were cheaper). They just go on so damned hard it has me wondering if I can use something to lube the ceramic part of the spark plug to get it to slide on better. Sill, it does go down when you tighten the bolt.

I have decided, I'm buying a new car tomorrow. Tired of fighting this in between work hours. Keeping the car though. Going to work on it when I have more time.

 

Going to buy a set of coils that are all the same brand as the original and see if that makes a difference.

 

I don't know if changing the coil brand matters. If I'm not mistaken you swapped them and the problem still stayed on cylinder 1. When you did the swap the problem would have moved.

 

Have you checked for an intake air leak? Honestly if you there is no leak and compression is bad on that cylinder with a foiled plug your engine needs to be overhauled. Those two together equals a bad cylinder.

 

If you want to lubricate the coil, get some "dielectric grease" from someplace like autozoned - it's made for sparkplug boots even back in the days of distributors & wires.