Idle fluctuation when cold

[Wirenut]

Okay my truck just started this after I installed the #10 plate and 370 injectors. The idle fluctuates between 300 and 500 rpm when I start it up in the morning. Ever heard a late 70's - early 80's Mack that idles like this? I think my truck thinks it's a Mack now. It smoothes out after a minute or so, but I was just wondering if anyone elses does this.

 

[illflem]

Mine with a #11 would do it for about 15 seconds, but I give slight throttle after starting, no problem then.