exhaust emission light

[vygec]

A few weeks ago, my exhaust emission light came on, vag-com reported the the temp sensor as faulty, so i replaced this, and cleared the codes, but the light has reappeared, ive tried clearing again, but its reappeared.
However this time, vag-com is no longer reporting the same error, the following are the fault codes now shown:

Any ideas, what to look for?
Ta
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Address 01: Engine
Controller: 4B0 906 018 CG
Component: 1.8L R4/5VT 0001
Coding: 11001
Shop #: WSC 00028
WVWZZZ3BZ1P067576 VWZ7Z0Y3014779
1 Fault Found:
17544 - Fuel Trim: Bank 1 (Add): System too Lean
P1136 - 35-00 - -
Readiness: 0000 0000

-------------------------------------------------------------------------------
Address 19: CAN Gateway
Controller: 6N0 909 901
Component: Gateway K<->CAN 0001
Coding: 00004
Shop #: WSC 00028
1 Fault Found:
01320 - Control Module for Climatronic (J255)
49-10 - No Communications - Intermittent

[Eddie]

Its either ur fuel pump on the way out or a air leak on the inlet side or the exhaust side of the engine wots the performance like has it dropped

[vygec]

performance is not quite what it used to be i.e. in each gear im forced to change much earlier than i used to, as the power runs out.
Is it even worth considering changing the MAF?