p0153-misfiring cylinder 4 again

[02LINCOLN]

A year ago I replaced the drivers side coils,plugs and valve cover gaskets and passenger side coils and plugs. About 2 months ago car misfired and had misfire on cylinder 8 but i checked the passenger side and found oil on 2 cylinders (cylinder 2 and 4) so i replaced the coils and plugs and valve cover gaskets as well as the cylinder 8 coil misfire. Somehow while working on the car the fuel pump relay went out and wouldnt start so i replaced that and it has run perfect for a month. Two days ago all of a sudden it stated sputtering and misfiring code came on and i had it checked the next day with codes-P0153 and "misfire cylinder 4". If cylinder 4 is misfiring and have to replace coil this will be the third time in a year replacing coil. Is there a deeper issue and are the latest codes related? This car has run perfect the first 4 yrs i have had it now its problem after problem

[danielsatur]

DTC P0304 - misfire on cylinder 4.
DTC P0153 - O2 sensor slow response.

Tran
4 8
3 7
2 6
1 5
fan

Check for any evidence of water residue, or rust on spark plug #4.

The COP covers will leak water in the spark plug Boss, it seems to roll behind the cover on bank1 were the ignition wires are going into the cover.

Don't over tighten the COP covers otherwise the gasket seal might leak like a bad valve cover gasket.

It's probably time for new upstream H20 sensors.

How did your secondary cam tensioners look?
How many miles are on this car?

[02LINCOLN]

I will look for the rust. oddly enough before this happended again i was parked in a driveway that was sloped before a rain storm. maybe some water got in

[danielsatur]

1) Clean contaminated coil oil/water COP with CRC electronic cleaner, or alcohol and a hair dryer.
2) Clear + reset code

It's probably a bad cowl cover diverting rain water onto a bad COP cover seal.

[02LINCOLN]

after getting home i took out the coil and plug and it was underwater. dried everything out and put back in started and ran perfect again.

[danielsatur]

Put a garden hose with just a little water pressure in the middle of the wind shield and watch the water roll into Spark plug boss #4 on a V8, and Spark plug boss #3 on a V6.