If it won't go over 2500 RPMS, it's the MAF. Since it worked before, likely wiring.
You need to determine where the break is in the wires. Is it right at the plug? You may need to get a razor blade and peel back the loom and look at the wires to see where the problem is, then just replace the broken section.
If it is broken at the plug, then yeah get a pigtail and wire it up!
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5.3 V8 Swap w/ Nitrous
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