So I get my Jeep running great. ('96 HO auto) Then it rains. Now it idles rough...like it's shaking all over the place, then I run some Seafoam, and it cleans it up. Then it rains again, same deal. After the rain if I drive it a while it gets a little better, but it's still not good. Other than buying Seafoam by the case for the occasional rain storm, I'm stumped. This needs a permanent fix!! It's had a full tune up recently...thank guys

 

What condition are your spark plug leads in? Might be worth investing in a good quality new set.

 

Secondary ignition is absolutely your primary suspect.

That includes spark plug wires, distributor cap (and rotor while you're at it). Are these new? If not, replace them.

A cracked coil can give you the same symptoms too.

 

The cap and rotor are about a month old, and the wires and ignition coil are about 5 months old, and I replaced the newer Bosch plugs with Champions last week...I suppose a bad new part is possible. What are your thoughts about moisture under the cap?

 

any chance you could be getting water in your fuel? Like a leaky filler tube or hole in the tank?

 

Hmm I'll have to check on that...def not a hole in the tank but I'll check the filler tube. That would explain why seafoam fixes it.

 

TJ is way more of an expert than me so don't rule out his diagnosis, like maybe you got a faulty new part or something. He called my problem first try! (Thanks again for your help on my fuel problems TJ!)

just wanted to mention water in gas because your description sounds a lot like when I had a hole in the filler tube on my old 4runner. Dry gas in the tank would fix it, everything else, electrical & fuel pressure was fine. Took a bit of digging to find that hole tho. Had my fill tube replaced and it was smooth after that!

 

Yeah TJ is the man. He's helped me on more than one occasion. Any help is good help though!