Recently my 99 V6 Accord has been having trouble starting when the engine is warm. For example I get up in the morning and go to the store I come back 15 minutes later and the car either starts and holds at a low RPM for around a minute or stalls all together. I'm not sure what the problem is as what I believed to be the culprit the duel pump and regularor where both just replaced. I'm at a loss right now any suggestions?

 

Last time a tuneup was done?
Last time the valve adjustment was checked/done?
Checked for any stored/pending codes?(use an obdII scanner/code reader)