1999 Durango Running Strangely

I have a strange shudder/misfire/hiccup in my 1999 Durango.
No audible noises, just this random shudder. Usually worse in the mornings/cold starts and gets slightly more intense with speed. I got an check engine light a while ago, which indicated a Piston 5 Misfire....I replaced all the spark plugs, and the car ran fine....for about 2 weeks. Now the shudder is back, but no check engine light yet.

Thoughts?

I have a strange shudder/misfire/hiccup in my 1999 Durango.
No audible noises, just this random shudder. Usually worse in the mornings/cold starts and gets slightly more intense with speed. I got an check engine light a while ago, which indicated a Piston 5 Misfire....I replaced all the spark plugs, and the car ran fine....for about 2 weeks. Now the shudder is back, but no check engine light yet.

Thoughts?

Could be a lot of things but I would start by checking out the plug wires. If you got a lot of miles on them might as well go for new ones.

a few days before i planned to check out the plug wires, the check engine light came on again. "Piston 5 Misfire."
as i was replacing the plug wires, i removed the number 5 wire and the metal contact on the distributor cap was HEAVILY corroded. so i got a new distributor cap too. how just that one got like that, i don't know. but now the car is running great.

thanks.

I had the same studdering, shuddering problem on the way to Munchen one weekend. (I'm in Germany) I felt this studder mostly when traveling uphill and it would also do it while I was idling. I discovered a few weeks later that it was my water pump crying for help. I also had an intermittent check engine light just as you indicated. I didn't check the wires but I felt it was time to replace them so I had the plugs and wires replaced while the water pump was replaced. After that it was happy sailing again. Good luck. J