I have a 99 Blazer and whenever it rains it misfires for a short time. Once the truck runs for a while and dries out it runs fine. I have bought a new distributor cap but haven't installed it yet. The repair book I have doesn't give great instructions and my husband isn't willing to try so I said I would do it myself and now......I am scared.

I figured if I can take the drive shaft off and put in a new encoder motor I can do this but after reading some of these posts it seems harder than I thought and is it my distributor cap that I should be replacing? I'm not sure anymore?

Any thoughts

 

Definetly sounds like a bad cap. If that's all you are replacing then its pretty easy. Just label the wires to make sure you get them in the right place and use some dialectic grease on the ends of the wires. Just a few screws and its done. Its the rotor that can be somewhat tricky, you just want to make sure it get it on the same way it came off.

 

+ 1 to the reply above. Three tips, you need Torx bits to get the screws out, the magnetized Torx will help keep from dropping the screws. Don't ask : ).
Two, the rearmost cap screw will be a bit difficult to get to. If you aren't 6 feet tall, a small step ladder and work light will be needed. And last, use AC/Delco parts, not the cheap chain store brands. Good luck, you CAN do it.

 

Once you remove the cap, look at the base plate of the distributor to make sure there is no debris blocking any vent hole. That can collect moisture and cause the problem you're having.