Need some help!!

I have a 98 Stratus. When the car is at idle (at a stop light or in heavy traffic) the oil light comes on. It's not constant though. It just kind of flickers. As soon as I press the gas, it goes back out. I assume it is the oil pump. My question is where is the oil pump and does the engine have to be taken out to replace it? Thanks.

take a manual gauge and check oil pressure at idle and at 2,000rpm and re-post!!