Hey everyone,
Post here to seek some advice. I drive a 2003 TL type S with 160k miles on it. I changed its ignition coils and spark plugs about two months ago, and the car drove super smoothly. However, about one month ago, I washed engine bay (using the water from garden hose, no high-pressure); since then, the engine has been struggling to start. Sometimes it started after 3 trials; sometimes, it couldn't start even after 10 trials. It makes cranking sound every time, which may suggest the battery and starter are working. I changed all the spark plugs again, but no luck.

When it occasionally starts successfully, my car also experiences miss fire when driving (wasn't there before the engine bay wash as well). It has been a while since the problem happened. The start problem got no improvement over time while the miss fire is getting worse. I'm pretty sure it's caused by the engine bay wash. Any advice is very appreciated!

(an interesting symptom, once the car got successfully started, it will be easy to start again within a few hours. However, after a longer time, say, one day, it goes back to its normal state)

 

If you're getting misfires, are you getting codes?

 

Yes, the code I got were like "cylinder 1 miss fire", "cylinder 2 miss fire", ..., and "multi cylinders miss fire". Sometimes I only got code from 1 or 2 cylinders, but at maximum I could get miss fire code from 4 or 5 cylinders.

 

That should be easy. Ignition coil is gone. Nr 1 or 2. Bring one from you pull and check first in 1 than in 2.