HondaCivicForum.com - New From Chicago

Hello everyone, I'm new to the forums and to the Honda world. I have a lot of newb questions but first a little back ground. I bought a red 1991 Civic 1.5L 4 speed hatchback last fall. I bought the car from a used car dealer. My first thoughts were: One, it was cheap and Two, I figured I could save money on gas. It has rust on both rear wheel wells connecting all the way around in the back. I put 400mph airplane skin over it and it's holding for now. hehe. The A/C doesn't work and I have issues with the air vent control from defrost to heat. I tossed a good stereo in it with boom box in the back and nice set of 6" speakers in the doors. That and a Sirius radio and I'm all set (Bubbabooy). It turns out I really love this car. I tuned it up, plugs, wires, cap&rotor, O2, fuel filter, etc... I change the fron struts and the front right tie rod end. Everything is good till one day on the way to work. I was doing my normal 80/85mph on the tollway and then when off the ramp I noticed it was running rough. I was low on gas so my first thought was it picked up some crap off the bottom of the tank. I changed the fuel filter but it didn't change the condition. I starts kind of hard now like it's out of time. Like it's starting against the compression. So, my next thought is, the timing belt. I swap out the belt, both seals, waterpump, idler pulley and set the timing. No change in the condition. Car runs like it's not hitting on all four. Loss of power and poor mpg. I did notice blow back coming out of the oil filler hole. Now I'm thinking maybe it's a valve. The air blowing back out seems to be cool so, so would that make it a intake? I pulled the valve cover and adjusted the them. It does seem to run a little better but not like it used. Is it possible one of my valves are breaking down or bent. I'm looking on ebay for a 1.5 rebuilt head to swap out. Is the right way to go? Or am I barking up the wrong tree? I know I need to do a compression test but my son miss placed it and I can't find it for now. Thanks in advance.