The Greatness· Registered
check your fuel pressure regulator. make sure its fully functional and that the vac line is intact. but you decription sounds more like a map sensor issue. if you have a firewall mounted senor check your vac lines. there should be one line off the tb that with a tee fitting that runs one line to the bottom of the sensor and one to the side of the sensor next to the harness connector. if this is correct then try swaping the sensor. for tb mounted sensors just make sure its well sealed. remove and inspect the o-ring under it. replace if damaged. if not replace the sensor. this may fix your issue. also make sure that your wires are correct. follow a scematic to make sure you have the right connector hooked to the right sensor. if mixed up the motor wont operate correctly. also make sure that the wires you ran for the 4 wire o2 and the vtec solenoid are in there correct location at the ecu. occasionaly you have to de-pin and re-pin a few wires at the ecu. you did run the wires from the engine harness to the ecu right? check your codes if you have a CEL.