Right i've plugged up that hose now idles alot better...but lost my Oil cap in the process (was adding oil)

replaced that now...
Have however found another problem....was wondering if this has any relation to the original problem of cutting out??!!
The thermostat dial is saying that my car after hard driving for an hour is 79 degrees where as the one on the MFA is saying 94 degrees... now i'm not sure if these are supposed to correspond to each other, in the past they have...im sure?
Can some one tell me is this is an issue and would i need to replace anything??
Any help would be much appreciated!! Thanks Guys!!