zr idle and power issues

hi i have a mg zr 1.4 2004 and it idles at around 1500rpm, ive changed the tps and the idle control valve but its the still the same, is there anyway i can use a multi meter to test the sensors, also i had some spare parts so ive also swapped the inlet manifold and throttle body, is there anything else i could try, ive also noticed it seems to lack power its ok to drive but when i put my foot down i would expect it to have more, does anyone have any ideas

thanks ben

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