help dont know what to do ???????????????

[nismo066069]

hello everybody i have a 1995 nissan maxima 5 speed. well first thing it takes a long time to start sometimes i have to try it again over and over about 3 to 4 times then it will start i dont know what it can be and second of all my car does not want to go high than 2,000rpm so i called my cousin and he was looking at it and he said clogged catalytic converter and i also have an exhuast on it but i want to upgrade the exhaust so i was thinking on putting a Greddy exhaust system but i dont know if i should put a hi-flow cat or a test pipe. so please help me before i do anything. thank you

[maxhopper]

If you install a test pipe, your either going to have to live with the check engine light on, or buy an emulator for the rear O2.