cheshire_cat

I have the engine light on and a P0100 Maf code. The engine starts and runs fine no jerks or stuttering when plugged in or disconnected. The Maf looks clean, is it worth spraying on a petrol engine ( well maintained ) I am getting a constant flow reading of 684. 06gms/ sec. ( plugged on or not) Having looked @ the plug I get ( ignition on) no.1 4.9v temp signal? no’ 2 ground no. 3- 12mv no’4 11v no’5. 3.12 volts Is the Maf duff or is it the main feed, no3? not doing it’s thing ( should be 12v?) any suggestions welcome