I have been working on my own car (classic car) ever since, but I'm now having trouble diagnosing what can be causing this.
Car details: 1982-Mitsubishi-Lancer-Mileage not really sure - Manual transmission, RWD, 5-speed. I used the car for like 2 years before the problem started occurring.
Some more info: Engine is a 4G35 (1.7L inline-4, chain driven, carburetted, points distributor) I believe it's be rebuilt before, not by me.
Problem: Car jarks (back and forth) when reaching RPM around 1.5K and smoothens out at >2K. This happens at almost any gear, mostly 2nd gear to 5th, I usually don't reach that high of RPM at 1st gear.
But I think I also observe a different feel at 1st gear while accelerating, it also feels like jerking but at slower frequency, cant really describe it. Maybe like a half second delay then surge and so forth.
Things I've done so far:
Replaced the ignition coil, hi-tension wires, spark plugs, changed contact points, verified ignition timing many times, carb cleaning/ re-built, still same response. I'm planning next to try another carb and see if it will improve. I really hope to have this fixed. Thanks Scotty.