The 2 main culprits behind this are the lower TMAP sensor and a possible break in the wiring to the lower TMAP. The sensor can get gunked up with oil from blowby and fail (a catch can will help reduce/eliminate this). If the crimps aren't done w/ the proper GM tool they can cause resistance isues and you get the surge. If the lower wires are soldered vs crimped and not weatherproofed correctly, again resistance issues can creep up and rear their ugly heads. Also cleaning the MAF and resetting the ECU helps greatly.

 

i was thinking this at first but he said that he had the connections checked so i ASSumed that eliminated that as an issue....maybe not....check em again

 

Of course that depends on how they "check" them. A visual check wlii do little good. You will need to check resistance across the crimp by piercing the insulation on either side of them with a probe then squeezing wiggling and heating the crimps. My troubles have always been connector contact with the AC comp or something else. Proper clearance with good crimps=no problems.