1978 Coupe DeVille has a rough idle...
 

I just picked the car up today, and was told it needed a carb kit.

It has a rough idle at all times: In and out of gear, any gear. When engine is cold or warm.

Sounds like a carb problem to me... But I have little to no experience with carbs, and carbed vehicles. Was told by a friend it could be numerous things.

Vacuum leak, plugs, plug wires, timing chain, valves...

Anyone want to give me a cheap and easy way to check for a vacuum leak?

Have any other suggestions?

Start by making sure bolts holding carb are tight, just a little more than snug. There should be a diagram on radiator support: trace vacuum hoses to see they are connected correctly. Next start engine see how it runs and listen for "hissing" sound if present follow the noise to find out why. If A/C doesn't out of outlets correctly check HVAC vacuum supply and reservior (vacuum ball).

Thanks, SlowRoll.

I'll probably check it out later today. I looked at it a bit last night, but didn't really know what I was looking for besides a hiss.