Ok I have an 88 RX7 non turbo with 186,000miles, I just got it. Anyway, the other day I started driving it, and it started to jerk really hard, so I pushed the clutch in and it idled normally, so I reved it to like 5 grand and it ran fine, so I was thinking it was fine. So I continued driving, anyway around 2k rpm's, it started to jerk really hard, so I pressed the clutch and reved to 2k and it still did it, it like has trouble staying there and shakes alot. So I replaced the fuel pump because in other cars I have had thats usually the problem, but it didnt fix it, so I replaced the filter and got new spark plug wires and plugs, but its still doing it. Someone I know said it could be the diff bracket or the MAP sensor but I don't know. PLEASE help me because I need my car for work on monday.

Thanks.