My 04 Dakota 4.7 overheated badly a while back.
Turns out, my radiator was over 75% stopped up.
I noticed today that, while sitting in traffic, when the temp gets up a little past normal, I feel a shudder in the truck, like a plug stopped firing.
When I get moving and get air flow through the radiator, it smooths out.
I am wondering if the overheating affected the plugs or coil packs??
Anyone ever have this issue before??
Any thoughts?
I would much rather change plugs than coil packs!

 

Better test for a blown head gasket very common with the 4.7 and overheating.

 

Agree with 98, bad head gasket.

 

There isn't any indication of a blown head gasket.
The shudder only happens when the temp gets slightly elevated.
If it was a head gasket, it would be constant and there would be other indications.
It's more like a plug starts misfiring.
I'm going to pull the plugs and check the color of them.
If they look good, I'll do more investigation.

 

It depends upon how bad a head gasket failure is and other factors. Are you losing any coolant?

Try this, when the electric fan comes on is that when you notice the shudder?

 

That does not compute???

 

How does it not compute??
A set of plugs is about $20.
A set of coil packs is considerably more dinero.

 

No, no coolant loss.
No other indication of any problems.
I put a new electric fan in when I reinstalled the radiator.
The fan runs constantly with the A\C on.
Otherwise, the temperature doesn't get high enough for it to come on, but the re is no problem when it is running or not.
The new plugs seem to have solved the issue.

Thanks everyone.

 

why would you ever need to replace all your coils one or two maybe but all?

As I said dose not compute easy test would be move any suspect coils around to confirm they are bad

 

A head gasket chemical test cost less than ten bucks, if you rent the unit from the auto parts store. You only have to buy the blue liquid.