914 MAP reading zero

Hi everyone,

Was flying my Sling 4 a week or so back and noticed my MAP reading 0.0 - not sure exactly WHEN this happened, but it was certainly during flight as runups and takeoff were definately reading normal pressures.  I was operating at around 50-60% throttle at the time in a slow cruise, dodging cloud and a little bumpy - increasing to 100% got the MAP up to about 5.0 before it fell again back to 0.0.  I didn't notice any drop in power, but then I did return to land pretty much straight away and have not flown since, so not sure if I will have full power....  

After landing and shutting down, the MAP jumped immediately back to atmospheric pressure (around 29). 

I suspect a loose or broken sense wire to the sensor, but would this be a plausible explaination for this behaviour?  From what I understand there is a seperate static pressure sensor feeding into the system, so with the engine off the ambient pressure is being indicated rather than the MAP, which is referenced from zero?

I'm hoping to spend some time this weekend checking the wiring to the MAP sensor - I have a gut feeing I know where a loose connection may be, but curious as to what (if any) effect a bad reading would have on the TCU and engine operation...