I have a 1989 Civic DX Hatchback with the D15B2 motor. Yesterday I changed my head gasket, valve cover gasket, timing belt, water pump, plugs wire, rotor distributor cap, oil, intake/exhaust manifold gaskets. The car starts up fine and idles beautifully. Revs fine in neutral. When I drive though the car hesitates. If i floor it in first the car goes nowhere until the RPM's get to about 4,000. I'm estimating cause I dont have a tach. When I drive the car I have to be 1 gear lower than I normally would be in to get any power. It's like 1st gear is 2nd gear, 2nd gear is 3rd gear, and so on. No backfiring. When I took off the timing belt I din't move the cam gear or the crank pulley at all. Any movement was made while the timing belt was on and they moved together. The car doesn't stall at all. What could the issue be? Where do I start troubleshooting? Thanks in advance.