Standard Weber injectors can handle about 260-270bhp at the standard fuel pressure.
A good chip only needs 1 bar of boost to reach 260bhp.
Either the chip is setup badly and needs 1.5 bar to get some results or your engine is running lean as hell OR your boost gauge is fooling everybody.
Is this a aftermarket boost gauge clearly marked showing pressure in bar of is this the standard Ford boost gauge?
How much boost is your boost gauge showing at a) engine off, ignition on and b) when the engine idles?
How to tell which map sensor? Measure the voltage on pin 15 with a digital voltmeter with the ignition on and the engine off.
A 2-bar sensor will have around 2.2 volt.
A 2.5-bar sensor (Std Escort Cosworth) will have around 1.8 volt and
a 3-bar sensor will have around 1.5 volt.
You can reach the pins by removing the top half of the connector to the ecu.
Unscrew at one end and clip the wrap at the other end.