7afe hard to start, stalling, surging Options

[SinisterWhisper]

My 7afe started having issues while accelerating. The car would shudder when you give it alot of gas. The engine is not throwing a CEL. I have replaced the fuel filter, and tried unplugging the temp sender. The fuel filter did not show and improvement, and the car barely ran with the sensor unplugged.

The engine is hard to start now, runs ok while warming up, but then will stall out of if left idling. Once I let it go to idle some times it will stall out when given gas. Once I reach 4k rpms it might jerk now and again but it seems fine. My exhaust also seems a little rich.

What else should I be looking at? The fuel pump? Could the O2 sensor cause this kind of thing? The distributor wires and plugs are less than 15k miles old, but could they have already gone bad?

[SinisterWhisper]

well i found a vacuum leak and cleaned the spark plugs. It started up fine and ran smoothly until it warmed up and then it started to surge again. School has started so I have just taken it to a mechanic so I can focus on my studies.