1999 GMC Suburban Service Engine

When light first came on code was pulled for MAF sensor. Replaced. Driven less than 10 miles, light comes on again. Code pulled showing bad MAF again. MAF replaced with OE brand from dealer. Driven less than 10 miles, light on again. Initially, when tested, no code can be pulled. Tested later code for MAF comes up along with cam position sensor. Rotor and cap replaced as well. Sensors replaced and a new pigtail added that connects to MAF sensor. Driven again less than 10 miles, light comes on. When codes are pulled again, none show up. Tested later, 2 down stream 02 sensor codes pulled as well as MAF sensor again! All replaced, light comes on at shop. Taken to local dealer who cant pull codes. CPU replaced. Driven 45 miles service engine light on again.

Fuel filter replaced and tune up completed 8 months ago. New transmission installed along with new catalytic converters. Additional tests were done along with the MAF repalcement to check the wiring and any potential vacuum issues. None were found. I am nearing the $2 grand mark on repairs and I still dont have a remedy. Local shop is frustrated and embarassed (didnt charge me labor the last two times it has been in) and the dealer cant seem to figure it out as well. Any suggestions or ideas short of pushing it off a cliff?