I have an '02 v8 4.6 mountaineer. It has been running terribly for a while, but only at op. temp.
We found out that some cap was spewing all over cylinder 4 in the back, and we replaced two hoses before finally replacing the stupid rubber cap. We thought that the engine was running badly because of the antifreeze in the spark plug, but it's been dried out and still isn't running well at all.

We replaced the Spark plugs, and fixed the leak, and got it tested at Autozone. Two codes came back, P1000 and P0354. So we replaced coil #4 and it still doesn't run well. Tried switching around to coils to see if the number would change when tested again, but it's still cylinder 4.

Idles at 500-700 when warm, and has little power, and slightly shaky when accelerating at low RPM. Runs perfectly at low temps.

I just unplugged the battery for 20 minutes and now the engine light is off, but it's still messing up. We thought it was misfiring.

Please any help would be great and thanks in advance.

 

One of the cylinders was wet. Don't know how it got wet, but I sprayed some b-13 chem tool in and it runs great.