1992 toyota celica runs rough (choppy)?

i got a 1992 toyota celica GT 2.2L DOHC engine as a project car. I recently put a new clutch, fuel filter, and fuel pump in it. When i turn the car on the RPM's will go up and down (usually between 600-1100) and will want to keep dieing and eventually does... I did brake the exhaust putting the engine back in place after the clutch job, but i dont think this could be an issue because it was doin it before that as well.. it has 198k miles on it. A few things i think it could be is 1. the timing belt, it says last replaced at 89k miles.. 2. The timing itself may be off?.. 3. a leak in the fuel line, im going to pressure test it when i get the chance. 4. it may have a compression problem??

Any advice, tips or hints are much appriceited!