Hey all having some issues with the 99 I just a motor in. It is surging while going uphill I can watch the tach jump back and forth from 1500-1800-2000ish rpm. Seems to do it between 45-55 mph. I have no vacuum line diagram so I'm unsure if its vacuum related. Its a 99 S10 Blazer 4x4 LT


Very similar problem like in this thread
https://blazerforum.com/forum/2nd-ge...on-surge-2832/

 

Also none of the orange indicator lights are lit up for the push button 4x4 if that has anything to do with it

 

Also while driving it I had the codes PO410,PO171, and PO174 come up. Also what is this it has a couple vacuum lines as well. Like I said very unsure how the vacuum lines are suppose to go.