sputtering and popping

I have a 1995 cav with 102500 miles. Today after work I started it up, and it was shaking pretty bad at idle. When I pulled out, it started sputtering and making a popping sound, but only at low rpms. Once the rpm's came up, everthing was normal. When I stoped at a stop sign, and pulled out, samething happened. The car was fine when I drove it to work in the morning.

Just got the car a week ago, I changed the plugs, air filter, fuel filter, and did a compression test which was good. I did all this before the problem started, and it ran fine for a week.

Any ideas?

To be more specific on the popping sound, it is backfiring thru the the thottle body, when the engine is under medium to heavy load. ie. pulling out, not cruising.