ok sorry, this is just another of those simple jobs we can do our selves like the loose pipe checking - bit like a spring clean.
The maf measures air flow drawn by the turbo and air ambient temp, the tmap measures manifold air temp and air pressure from the turbo - both are used to calculate injections on the ecu map.
The tmap will get caked in soot over time from exhaust gas recirculation, and this will effect the reading the ecu gets.
The tmap is sighted just beside the dipstick, it is bolted to the manifold with one bolt (a torks t-30) It can be unplugged by lifting the yellow locking tap up and squeezing the raised tap and pulling, but there's enough room to leave it plugged in and clean if you want.
I use carb/brake cleaner with the pipe nozzel to give the sooty area a good clean and let the cleaner evapourate off, and re-assemble.
I've added some pics of location, and before and after cleaning.
There's no garrantee this will fix your problem, but it will help.