3800 uses a MAF (Mass Air FLow), not a MAP (Manifold Absolute Pressure)..but I guess that is what you meant. Just one thing not clear : will the drop in speed occur only with the cruise control ..that is, if you throttle yourself (slowly so as not to shift gears), will it maintain speed? Occasionally mine will do that (loose speed) on cruise, going slightly uphill, while I can maintain speed if I throttle myself. I cannot repeat that at will, just random, so I have not really investigated the cause.