High map sensor voltage that doesn't change could indicate an open in the signal wiring.

Unplug MAP, measure voltage directly at the connector.

If you see 0V it's open.

If it's still at 5V then it is a ECU/Module control problem.

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1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.