p2188 (system to rich at idle bank1) help please :(

[peynut81]

just changed my front lambda sensor now this fault has appeared and car is running like a bag of ££££.
when you try to go there hesitation the car almost sounds like no fuel stumbles for a second and then goes but with reduced performance.
the mpg has gone down to 17.5mpg
also when you brake to stop say at traffic lights all the lights flicker n the revs start rising up n down same happens when you rev it stationary to. i would assume alternator on the way out i have cleaned maf sensor with electrical contact spray thats not helped any but i am no expert hence i'm asking you nice people

i know the other fault code is for the clutch position sensor i have on order from volvo

thanks in advance for any advice

my car is a 2002 volvo s60 2.3 T5 SE