Knock sensor replacement

Ok guys so recently I noticed that my 2000 3.4L was running sluggish and it finally shot me a knock sensor code. I replaced the knocksensors and harness (oem). Also the intake gaskets. After finishing I started her up and she's idling great! But while in neutral giving gas it sputters and is rough getting up in rpms. Once there it sounds good. Also am seeing white smoke during cold start up. It looks like its coming from the center of engine. My question is what could be the issues for this? Do i have a vacuum leake some where? I though it was jist burning off some coolant I had spilled but ive started it several times same smoke and is accelerating the same. Could the manifold gasket be bad? Ill admit I did go the cheap route with the gaskets. Thanks guys

 

Did you figure this out? My educated guess would be a bad fuel injector.