04 Sonata v6 running rough after rain
 

I have a strange problem that occurs after a good rain. The car will run fine for 5-10 minutes and after that it sputters and misses. It will idle fine but as soon as you give it some gas it sputters it also will not shift out of 1st gear till after 3000rpm. It doesnt stall but has very bad hesitation. I have scanned for codes but nothing shows up. It is definately moisture related but I am not sure if it is wires, coil etc. Anyone have the same isssue or know were to start?

Did somebody power wash the motor in the past?

Chances are you have corroded connection on one of the sensors someplace. I'd be pulling off modular connections and looking for corrosion, spray down every connection with electromotive cleaner as I inspect them. Start with things like the MAF, the IAC, TPS. Continue with transmission sensor, etc.

My 2003 has the same symptoms, but it only happens after it has been sitting for a couple says and it has rained (not every time it rains). Took it to Autozone and they scanned the computer for codes. No codes. Also, no Check Engine light. I went ahead and replaced the spark plugs and plug wires and the PCV valve. I did notice what looked like residue on the plug wires where they may have been arcing to each other, but no visible cracking or holes in the wires. It hasn't sat for a couple days yet, so I will probably find out if I can let it sit for a couple days and we get a good hard rain.

Oh by the way, yes, for me too, it happens after 5-10 minutes of driving (not before that) and it idles nice and smooth, just stutters and sputters when accelerating and revs higher than normal in 1st gear before shifting to 2nd. Very spooky how what you're describing is just what I am seeing too.

Note: This is the 2.7L V6 - the car has 144,500 miles, and this is the first time I had replaced the PCV valve, the plugs, and the wires.

What was the fix for this? my Santa fee been stalling ever since i went to an automated car wash......

For me, there was no fix. It just stopped happening. It hasn't happened in about a year (knock on wood).