I have a strange problem it began when i have to change the oilpump. I have bought for my 2.5sti block project a upgraded oilpump from Lateral, the Roger Clark pump. The pump was not good, the plunger was stuck in it. So I have 10bar of oilpressure.

Oke change the RC pump with a new oem subaru pump. The switch was going well, but some strange thing was happened. The car did not drive smoothly after the changing. When i rev from 1500-2500 the car hold in for a second and again and again untill it is over the 2500rpm. You see the rpm needle dancing up and down and up and down.
This is in all gears sometimes heavier, especially when it is cold. It is so heavy you can make a milkshake in the car. But if i rev quick then you will not feel this shaking?? Strange isn;t

I have changed or cleaned the following sensor or parts:
Cranksensor
Camshaftsensor
MAF sensor
Lambda sensor
Check all vacuum hoses
Spark Plugs
Spark wire

I have a unichip and the map is based on a 2.0l block. Will this cause the problem, i do not think so. Because it drove good before i changed the oilpump

I do not know where to look anymore. Do somebody knows this problem or have an idea where the malfunction will be, let me know!!

Regards Mike (Netherland)