Weird Problem...any ideas?

[Lankhimself]

My truck has been doing this for a little over half a year now. It's a really weird thing. Say the truck is sitting overnight and it rains, I start up the truck that morning and the idle is rough and the exhaust sounds like it's "chugging" and feels as though the truck is going to stall. It still drives fine and backs out of the driveway, but the weird idling and exhaust note goes away like clockwork once I'm halfway down my road and then everything sounds and feels normal.

The thing I don't get about this is the truck ONLY does it after it rains. If it's sitting outside during a dry night with no storms or rain it starts up normal the next morning.

I just cleaned the IAC with electronics cleaner and then compressed air, maybe it's time for a new one-it wasn't that dirty but the one I've have in there was replaced a few years ago. It rained last night and I haven't started the truck yet today, but I'm almost positive it will do it once I turn the iginition, like always.

Anyone have any idea what the problem here is??
Thanks guys.

 

[NoogaX]

Have you checked your plug wires?? Sound like one or more may be in bad shape and when it rains, the moisture can cause the wire to short to some thing. After you run it for a few minutes it may just be drying things out. Are you getting codes or does the check engine light come on?

Hope this helps and good luck.

Butch

 

[Lankhimself]

No, no CEL. I haven't gotten the codes read either, but I assume if I got the codes read, it wouldn't show anything because after driving to an automotive place it wouldn't have the problem at that point. Who knows.

 

[hworksinc]

Is your air filter and MAF sensor clean? According to your sig you have a K&N - if your filter is dirty or under-oiled moisture could be condensing on it. If it's over-oiled the MAF sensor may be contaminated and moisture is throwing it further out of whack.

 

[Willard]

I'm gonna second the plug wires, they are going to be the most sensitive to moisture. I've seen some older vehicles run noticeably worse in rain. Have you ever replaced the wires?

 

[ttavenieriii]

hey

i read ur post and i too had the same problem and know mine is fixed let me help a little let me know if this too helps u
i cleaned the idler air thing with that electrical spray try doing the same to the maf sensor also i went to napa and had custom 10mm wires made for the truck and changed my plugs to there high performance plugs after i did this i havent had anyproblems yet some people say its because the the maf sensor but i can say one thing the new custom plug wire help with the performance it seems to run way better and i have a little more take off when im sitting still in mud up half way to the windows lol like i said go to napa i had the wires mad by my house in st cloud florida but im pritty sure any napa can do it.

 

[Turdle]

I'm going to suggest the additional condensate on the ( heated)02 sensors is causing them to warm up more slowly.

 

[Lankhimself]

K&N Filter was brand new Last august, it's got a wrap on it and has never been cleaned or oiled. It's the same as it was out of the box and is very clean.

I had a shop replace the plugs and wires two winters ago when I had a huge engine overhaul done. Should I replace the wires? How hard is this to do? I've never done sparks and/or wires by myself.

 

[Lankhimself]

bump. Anyone else want to chime in?

 

[gijoecam]

Assuming it's the 4.0 SOHC, not the OHV, Lower intake manifold gaskets. Mine started off just like that. First only on cool damp days. Then on just cool days. Then on very cold days, it lasts a little longer... Common problem, simple DIY solution. Search for 00M12 and ye shall find.

-Joe

 

[marragtop]

Start with the wires since the problem is moisture related. Wires can go bad within 2 years. The best way to access the plug side of the wires is thru the wheel wells. With the price of gas what it is, you might also want to consider doing the plugs while you have the wires off. How many miles since you had the plugs/wires done 2 years ago?

 

[Lankhimself]

Assuming it's the 4.0 SOHC, not the OHV, Lower intake manifold gaskets. Mine started off just like that. First only on cool damp days. Then on just cool days. Then on very cold days, it lasts a little longer... Common problem, simple DIY solution. Search for 00M12 and ye shall find.

-Joe

Not an OHV...but I think I've seen a DIY on here about replacing the lower intake manifold gaskets on an OHV engine. That might be the problem.

I've put about 20k on the truck since that engine overhaul when the plugs and wires were done. I'll start there to see if that remedies the problem.

 

[mshuler009]

If it does it when it rains or is extremely humid, plug wires....