Hi all i have a 2006 vauxhall vivaro 1.9 dti a few months back i had a diagnostics check on it and it came back with a faulty maf sensor so i bought a new one off ebay for £30 i fitted it and it seemed ok but not alot better i had another diagnostics check on it and it came back with three different fault codes to the original code these are as follows P0100-not present (maf sensor) P0400-not present (egr valve) P0113-not prsent (intake air temp sensor) after a bit of research it seems the cheap maf i bought of ebay has a bit of a bad reputation for being of substandard quality so i bought one from a local motor factors for £120 i fitted this cleaned the egr and took the van out for a spin and all seemed to be well the van pulled alot better idle revs didnt drop as they did before no lack of power when cold and the black smoke had dissapeared sorted i thought got back home and ran another diagnostics and annoyingly i got the same 3 fault codes i put this down to my opcom being rubbish as everythimg seemed so much better but this morning a day after fitting the new maf i started the van up and all the probs where back again it runs better than before but still the smoke and the dropping idle revs. The revs drop to nearly 0 when i brake for a junction it dosnt quite cut out but is close to it as soon as i release the brakes the rvs go back to a normal 850? im now thinking perhaps ive disturbed a dodgy wire going to maf does anybody have any ideas on how i can check this any input would be appretiated.

many thanks graham