My mechanic tells me that to get my 2002 Mercury Sable V6 to run propoerly, I have to replace my non-working a/c compressor in order to get my DPFE sensor to operate properly. Really? What does a non-working a/c comporessor have to do with the operation of the DPFE sensor? The a/c hasn't worked for months and hasn't been turned on. I took it in with 'check engine light' and stalling, stumbling. The code called for a new DPFE valve and he tells me the a/c compressor has to be replaced too? AT $1,200! Am I crazy or does this sound right?