Most of the time my truck runs perfectly fine. But, every now and then, like when it's raining or after it has rained and it's still really humid the engine will idle rough and stumble intermittently for a couple minutes until it warms up. Then it's fine. I have sprayed water over the engine and components when the truck is running to see if I could duplicate the problem but it just keeps running fine! Is there a component that could be affected by a higher level of moisture in the air when it starts to go bad? I have had issues with wet weather off and on since I got this truck and I'd love to solve the problem!

Thanks

 

Seams like you have an odd duck.. My 06 FX4 has 62k on it and never have i had any of the problems you are saying. It has been real hot and humid here in NJ for the past week and we have had afternoon thunder showers all week and never a problem out of my truck. Wish i could help you. Hopefully someone with the same problem will chime in and answer your question.

Mark

 

Yeah, the moisture has to be affecting the way some component operates. It runs fine when it's dry outside. It usually acts up after it rains or is raining. The last time this happened, it had been raining and the ground had just dried up. I had not been driving since the previous day when it was nice out and I didn't drive during the rain at all. When I started the truck the idle was stumbling. Once, in the first couple minutes of driving, there was shudder in the truck for several seconds and the rpms dipped down. Right after that everything was perfect for the rest of the drive and has been since. That was a couple days ago.

 

Have you had your truck scaned for any trouble codes?

 

I don't know about your specific situation, but I have been working with electronics for a long time, and moisture and electrical components never quite get along. So while time consuming, check every and all electrical connections, including any sensors under the truck which could be most trouble. Just look for anything that might have come slightly off allowing moisture in. Everything should b in plac nice and snug and pretty clean. If something looks all crapped up from the outside, clean it up carefully disconnect it and plug it back in. Inspect the pins while apart to se if they have any green or white corrosion, then you also have to delicately clean up the pins etc.

 

Did you check the O2 sensors? They might get overlooked during your hosedown....just a thought.

 

The FPDM would be safe from a hose in the engine compartment too.

If they salt the roads in your area, it may be worth dropping the spare to see if it looks as ugly as others have described theirs.

Or just shoot some water up there first and see if it starts cutting out. It may flat croak though if it is all corroded up.

 

After disconecting any plugs and cleaning if needed, use a little bit of di electric grease on the contacts before re-connecting them to make them more resistant to moisture, and to help keep the contacts clean.

 

I have checked all electrical connections that I could see. I always put dielectric grease on electrical connections(just bought a quad and unplugged every connection and filled with dielectric grease before I even rode it lol). What I find odd is that this problem occurs after it has rained and the ground is dry before I drive. Not much can get wet in this circumstance. It happens as soon as I start the truck and haven't moved it yet. Very annoying!

 

If you ever have these symptoms @ night open the hood & look around with the engine running, my old 92 had a similar problem,. At night I saw the light show, arcing between plug wires. .....I don't know your model year, but if it has 'em and there are over 50k miles just replace the plug wires and disributor cap and rotor.

Good luck

looks like plug wires and dist cap might not apply as this is the 04-08 forum

 

delete....

 

nlf remember, when all that rain is evaporating it's going up into the air, trust me I'm no scientist, its like a vapor and most likely that is when the trouble starts, not from the rain itself. When you think about it the concentration of moisture is probably very high during that drying up period and that's getting into the works. The next thing is probably take off all the battery and ground connections and clean them real good. How old is your battery? After that put some of that red battery protecant spray on. Then on to inspecting and testing out the ignition stuff. Also do you think possibly the fuel is cutting off somehow, maybe pump connection cutting out? I'm just throwing stuff out to brainstorm.

 

I have been going through this off and on for months. I have checked many things over that time. There have never been any codes in that time. I have checked many connections as well. I had an issue with water coming through the firewall where the main wires come in and I fixed that after having to replace my fuse panel.
Another thing I should mention is that this is an intermittent problem. The remnants of hurricane bill passed through this morning. High winds with rain and very warm. I got up at 5am to go to the gym and it was only misty at this point. I figured the truck would definitely stumble a bit after that.... perfectly fine

I'm wondering if there is any sensor in the air intake that could be affected by moisture... airflow sensor? The worst thing is that if I fix it I won't be able to tell right away because the problem occurs sporadically
I'll probably just put up with it for now and wait for something to actually break!

 

Yep no doubt this is frustrating as all intermittent problems. That fuse box replacement certainly brings another light into it. Have you rechecked around there and looked for any possible corroded contacts from previous water? Pull out and put back every fus nd check everything. Hassle yes, but otherwise you can't be sure. OK good luck!

 

Yeah, good idea. I'll recheck some stuff asap.