93 villager problems

Yesterday I bought a 93 villager, today it appears that was a mistake! The van will not blow heat at all. I changed the thermostat today and now not only is there still no heat, it began overheating, and the fan belt started squeeling. Also while driving, once in a while the engine seems to loose its power, almost like its not getting fuel, but if i take my foot off the gas it idles fine.This only happens for about half a minute then its fine. Are these problems related? I was thinking the heater core may be plugged...but would that cause the engine to miss? If anyone can give me any advice on what to do I would greatly appreciate it.

No heat/over heating; blocked heater core or air in coolant system.
Loss of power;may want to try a new fuel filter.
Problems not related.

It turns out the van was air locked.....as far as the bad miss goes ive changed the plugs, wires, fuel filter and distrubitor cap and it still has the miss. I thought id try the o2 sensor next, can someone tell me where to find it?

How many miles are on it? Explain the mis. What type of fuel are you using and the overall condition of the van.

I may be able to help with your engine problem. I had the same problem. Check all your vacuum lines. I found bad line connected to my vans EGR valve. Replaced and fixed the problem!