Misfire Issue when it rains

StephenCasiday said:

i will try and look, i did a spray test, and it’s also raining, but i sprayed water all around the pcm, and all around where 6’s coil is and the plug and wire and even back behind the intake where the lines run and nothing

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Ever figure this out? My 17 is doing the exact same thing, cylinder 6 when it rains or you wash it...

blizzardrunner said:

Ever figure this out? My 17 is doing the exact same thing, cylinder 6 when it rains or you wash it...

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First, welcome to the forum, from Oregon.

Second, it really would be better to go to the correct section for your "17" and post the problems. You will get more responses. Plus, give more vehicle info, other than 17.

In wet conditions, I would always look at plug wires first. Are you getting a misfire code? If so, swap the wire with #4 and see if the misfire code follows the wire.

The problem doesn't necessarily have to be with cylinder 6; it could have a completely different cause. I once had a BMW where the catalytic converter was clogged, and it only ever misfired on cylinder 2. I tried everything and replaced parts until I finally replaced the catalytic converter, and that solved the problem.

Your problem, of course, isn't due to a clogged catalytic converter; that can't happen in the rain.

But it could be, for example, that a lambda sensor cable is the problem. When it gets wet, the engine receives incorrect lambda sensor readings, leading to poor combustion, which in your case is causing problems on cylinder 6.

In any case, water in the rain is more of a problem at the front of the engine and underneath. Very little rain reaches the top of the engine or control unit.

I would put the car on a lift and inspect the cables from underneath.