Idles at 1500 rpms when cold and is real jerky. After the car warms up the idling goes back down to normal but the car still jerks when I release the gas and when I first push on the gas. Its fine below 1500 rpms but when it reaches 1500 its like a rev limiter hits on. I've replaced the O2 sensor and exhaust manifold. It ran for about 3 months with no O2 sensor. Any help would be greatly appreciated.

 

***Could*** be Fuel supply issue... i have never run into a problem like that, but the only things i can think that would cause that is either A. Fuel B. Ignition so... check your distributor, first off from there... ya not to sure... it would be alot easier if one were there to actually take a look... but perhaps someone else on the forum has had this issue...