I have a d16z6 in a 90 crx si. I installed a skunk2 cam gear and put the timing to tdc. The timing belt is a little loose. The problem is that the car runs and idles fine for the first 15 mins. then after that it will have a rough idle and have a small faint gas smell. no smoke out of the exhaust. through out the rpm range it runs great. every-once in a while the o2 sensor will come on. (im guessing bc it is running to rich). When I turn off the car and open the gas tank cap a lot of pressure will wizz out. Sometimes it won't want to start until i let the pressure out. I had that problem before the engine(the not starting). any ideas?? im fresh out. thanks

 

anybody?