Why does the same DTC come back after R&R Sensors and Cleared the DTC, ECM Bad?

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I have a 03 Chevy Tracker 2.0L 4X4 AT It ran Perfect when I first got it -But Started bucking, Horribly like it was missing on 2 of 4 cylinders. MAF DTC So I cleaned MAF. Run perfect again for about 100 miles & Repeated the Bucking. DTC said Replaced the MAF, MAP, Knock, ECT, OX, sensors & Sparkplugs & it still has both MAF Low & High Input-DTC, ETC Low Input, Knock High input, & undefined DTC. Unplug/Replug Wire harness under Dash on Drivers Side. MAF Low is now Gone, But, MAF High Input, ETC Low, & Knock Sensos High inputs Still Come Back. WTF Help I have an Auto Boss V30 Elite & Monitor all sensors - MAF stays at 239.4 all the time and I can unplug it with no change but, when I remove MAF from in take Tube with it plugged in - 239.4 reduces slightly & engine Stops. Also, EGR is always at 0.0 All other Sensors Look like they are Functioning correctly. Would you get an ECM Defective DTC if it is bad,?.? Help Thanks