My wagon has some leg in accelerating. It is a stick and around 2,000 rpms there is a lag, it does not want to go any faster. To me it feels like an auto tranny not wanting to downshift on a hill. After 3400 rpms the leg is gone and the power is back. It has a completely rebuilt engine, seals, gaskets, a new crank and one new rod. I found out the answer to this problem and it was the knock sensor. Below the knock sensor someone helped me place a small donut shaped gasket and this immedialetly fixed the problem. I just got a new knock sensor today and thought that it would solve the problem for good but it is back. The homemade gasket is not underneath the knock sensor. Has anyone had a problem like this and could it be part of the rebuilt engine?