What's the problem with my new intake?

i have a '01 celica that i just installed a cold air intake on. after the install the check engine light came on. i ensured that all vacuum lines were installed and all sensors and plugs were plugged in. the engine doesn't seem like its getting enough air or the air/fuel ratio is to lean. also the exhaust looks like it might be leaking a little gas, because without the air the fuel isn't igniting well. whenever i give it gas the engine hesitates then kinda kicks on. today i thought there might have been a leak in my pipe somewhere where it connects. so i put all new rubber seals on each line and one where it connects to the housing. the check engine light still didn't go off despite the engines rpm's didn't skyrocket this time at start up. ive been troubleshooting this problem for 2 days now and i need some advice on other things to do. please help!!!