2004 GMC 1500 had a v6 4.3
Someone put a 5.3 from a yukon on and the ecu to match.
Cannot even read the ecu we get a "Checksum Fail" half way through reading.. we tried grabbing a couple of tunes off the forum to force through to see if that did anything but it wont allow it to write.. we dont want to waste a bunch of credits.
Anyone have any ideas?
