I have an 87 firebird (305). It's been running pretty well except for disliking the cold. This moring I let it warm up like I always do but when I started out, the car began jerking like I was letting off the gas and flooring it and letting off again immediately.

It has done that a little when I don't let it warm up enough but this didn't get any better. There was also a noise like a small pop (almost like a small backfire sound) under the hood as this was happening. It is really bad when I take off but if I can get up to about 2nd gear and keep the speed steady, it pretty much stops.

Can anyone tell me what might be going on? I've only had this car a few months and I'm doing my best to learn as much as I can but I'm really a novice. Haven't done too much with it except for changing the spark plugs, wires, distributor, and rotor a few weeks ago. (Didn't get the 2 plugs that are hardest to reach yet.)

 

For the back two plugs, go from underneath the car. You might actually be able to see them....

Check your timing. I suspect that it is off.