'97 2.4L crankshaft position sensor (wet ecm?)

[sandoz]

A couple weeks ago the check engine light on my Z24 lit up and it immediately started running bad. It still had all the power but every once in a while it would have a spell where it would jerk like the engine wanted to cut off but it would recover quick enough that it would continue running. The check engine light seemed to come on right after I ran the right side tires through a big puddle of water. I have an OBDII scanner and it was reporting crankshaft position sensor and camshaft position sensor. I let the car sit for a day until it stopped raining. After that the car ran perfectly for a whole week until it rained again. It seemed like if I went 5 mph under the limit it was slow enough to keep the car running ok. But now, it gets so bad that it is hard to keep it running long enough to move around in the driveway. Here is what I have tried so far:

- Replaced the crankshaft and camshaft sensors and cleared the diagnostics. The camshaft diagnostic is not being thrown anymore, now it is just the crankshaft sensor.

- Went searching for the ECM to check for water damage, wiring problem, etc...

- First looked under passenger side dash based on a guy from Autozone. I didn't see anything there but while I had the dash apart I fixed that annoying squeak behind the instrument cluster with a piece of cardboard.

- I then took out the battery, air filter housing, and resonator because some other post mentioned the ECM being under there and I had noticed a bunch of wires leading there. This turned out to be just a big wiring harness that ends up passing the wires through the firewall. I took this apart anyway to check it out and it had no corrosion so I just lubed up the seals and put it back together.

My next plan of attack is to look in the passenger side wheel well for the ECM as I saw in some other post (and I see that half of the big wire bundle goes under the radiator in that direction). I hope to find that water has gotten to it and is causing my problems. Is this where I will find the ECM and do you all think this is the likely problem? The guy at Autozone said the new crankshaft sensor may also be bad and I should return it and try another but they are out of stock at the moment.

Anything you can suggest will be helpful as I am almost out of ideas. Oh, one of the first things I did was to replace the spark plugs and boots since the car is up to 77k miles and they had not been replaced yet... but I didn't expect for that to have an effect on my sensor problems.

-scott

[sandoz]

I found the ECM which was indeed in front of the passenger-side front wheel well. I removed and inspected it and did not see any signs of water infiltration in the connectors. Autozone quoted $119 for a new one and Advance has some GT (or GP?) brand for $109 shipped. If it were only $60 I would go ahead and spring for one but I don't want to just throw around money where it isn't needed.

Does anyone have an opinion on which they think is most likely?
1. The ECM is bad
2. The wiring is bad
3. The brand new crankshaft position sensor is bad

I am going to try and get things put back together tonight just to see if reseating the connectors fixed it. If I am still having the CPS problem I don't know what step to take next.

-scott

[sandoz]

Well, after I took out the ECM and put it back in, the engine is running perfectly and throwing no diagnostics. I don't know if it was reseating the ECM connectors, or if moving the wires around fixed a short/open, or if something just dried out, or if the new crankshaft sensor is just behaving itself for now. The problem had gone away for as long as a week before without me doing anything, and seemed to be triggered by moisture, so I am expecting this problem to crop up again the next time it rains. We shall see... I would greatly appreciate someone else's take on all this.