misfire and sputtering on acceleration! Running rough!
 

My 240z is sputtering, coughing and misfiring during the first 15 minutes since cranked. Is this normal? I have to run it with the choke lever pulled until the temp reaches to half of the temp gauge. After that it runs rough. I have cleaned all the plugs to see if it solves the problem. Airtex 8012sx electric fuel pump is just pushing 3.2 psi. Coud this be the cause of the symptoms addressed?