i just swaped a b16 into my 91 dx hatch, everything with the swap is done but its having a running problem. it runs good when its cold but when it warms up its like it has no power or no gut, its not throwing any codes, the injectors are fine, ive checked everything else i dont know what do to..........i might need to replace an o2 sensor when i go to the parts store to get one what am i going to look for?