'03 D II, 98k
According to my code reader, I've got two cylinders that are misfiring. The misfires are definitely noticeable, truck stutters and bucks a bit. SES is flashing intermittently.
Are plugs and wires the first-line action I should take? Both were last replaced at 49k.
​​​​​​ What would the next logical step be?

Thanks for any advice.

 

Its either plugs, wires or coils.

Which 2 cylinders are misfiring?

 

It's cylinder 5 and 8. Thinking bad coil pack because 5 and 8 are on the same pack?

If the coil packs are good, what's the next step?

 

If the coils are original I’d replace em.

 

 

I was getting 2 misfire codes, on the same pack, and it ended up being my O2 sensors .I have no idea how, but that's what fixed mine .

 

I had a 300/308. Replaced wires and plugs - no help, just looked better. Replace coil packs and she's running smooth with no codes.

 

What mileage does the truck have now? I'd replace coils, wires, plugs. I'm assuming you have no other codes?

Do NOT drove the truck until this is fixed. You'll melt your catalytic converter if you do, among other possible issues.

 

The truck has 98k io it. When I bought the truck it had 49k - replaced the plugs and wires at that time.

In reading several other posts, I bought 2 upstream o2 sensors (Bosch), 2 new coil packs, some MAF sensor cleaner, and even a 22mm o2 sensor removal tool. All the stuff above is in addition to plugs and wires I already planned on doing.

So, in order of attack:
Plugs and wires, if that doesn't solve it,
Change the coil packs, if that doesn't do it,
O2 sensors, if still no luck,
Clean MAF sensor

If after the steps above don't resolve, I'm at a loss. I'll be tackling the repairs this weekend. I'll post back if I have success or not.

Thanks for the suggestions.

 

Coil packs are $50 for both, and it's nearly impossible to change plug wires without removing the upper intake manifold ($6 gasket).
It's worth replacing coils when you do the wires and plugs.