Odd symptoms

[Eeffinger at conestogac.on.ca (Edward Effinger)]

Steve, it is possible that a weak battery could cause those symptoms.
Ed 81'S
 
 
Looking for advice -

My '86 16V has been doing odd things lately. While idling at a stop light, my the RPM's have been jumping from 900 to about 2500 yet the engine doesn't race with the meter. Also, the other day, while stuck in major NY city traffic, the car simply died twice (luckly, the first time I was on a slight downhill incline and rolled to jump-start it & the second time I asked the guy behind me to give me a push in order to jump it). For the rest of the ride home, I had to keep the engine racing slightly so it wouldn't stall again. Also, everytime I accelerated, the car would buck and hiccup. Oh, and the fuel pump under the back seat was unusually loud. What do you think I have going on...dirty injectors, grounding problems, bad oxygen sensor, bad fuel pump or filter? 

Thanks for any advice ahead of time, Steve