Distributor issues on long trips...

[Mike Mat]

I bought a 1997 K1500 305ci 5spd for use as a plow truck and a run around on the property for weekend work. It had over 200k miles when I got it.

Problem is after new plugs, wires, cap, rotor, water pump, t-stat, tires, belts, tensioners and all fluids changed it runs great. Runs so well I put another 20k on it the past year and a half!

While it’s been on trips 60-75 miles regularly with no trouble, recent trips of 250-300 miles have presented a problem. After a 250 mile trip with no issues, the next morning the truck started but without cylinders 2 and 4. I replaced the coil, ignition control module rotor and cap and was on my way. Another 300 miles later, while I was driving at highway speed, I had the same problem. I limped to the next exit, replaced the cap and rotor in the parking lot of a Napa auto and made it home. Since then it runs fine on shorter trips.

Thanks for reading and any help you can offer.

 

[SUBURBAN5]

How do your plugs look? Have you checked them?

 

[Mike Mat]

How do your plugs look? Have you checked them?

Plugs are good. Relatively new. After change in cap and rotor motor runs great.

Thanks for the reply.

 

[SUBURBAN5]

Your old wires and cap/rotor. Any unusual wear?

 

[HotWheelsBurban]

Your old wires and cap/rotor. Any unusual wear?

Yes, you need to check this, because you could have a loose or slightly bent distributor shaft. Rare but it does happen.

 

[Mike Mat]

Wires seem good. Here’s a pic of the rotors and caps I replaced. They don’t seem to bad to me either though.

 

[Mike Mat]

View media item 32459

 

[Mike Mat]

View media item 32458

 

[SUBURBAN5]

Hard to see a close up but they do seem normal. How long have you used that brand?

 

[Knuckle Dragger]

Picture is no where near detailed enough to see carbon tracking in the cap. Look closely inside the cap and see if you have faint tracking from on post to another. All it takes is a little moisture and some time to do it. Misfire can be intermittent like you describe.