depending on if you replaced your intake manifold, it might not be sitting all the way flush, i put a obx r drag racing intake manifold on my h22 swap and i had the same problem as you and did everything you have been doing and in the long run i had to shave down the surface of the intake manifold because the 1992 h22 differed from the newer model, so u might want to check on that..... sorry thats all i can help