Can some help please?

[chadvicki]

I am having trouble with my truck idling smoothly. While in drive I am at 600rpms. It will idle smooth then I feel like a bump or hiccup and the rpms drop one tick or 100rpms. This happens quickly and every 5 to 10 seconds. If I put into neutral the rpms go up and the idle is rough. Here is what I have done so far:

1. Replace ignition wires
2. wire looms to keep wires off headers
3. replaced cap and rotor
4. replaced all vacuum lines
5. new fuel filter

After the cap and rotor it was really good for a day. Now its back to the same old thing.

Any help would be great.

Thanks,

Chad

Any ideas what I could do next? Carb rebuild or swap?