MG ZR Pulling/Jerking while accelerating

I've recently had a problem with my car pulling when accelerating fast, It only started the other day after I washed the car.



I have a Pierburgh MAF with a MAFAM connected on standard Injectors...



I disconnected them both, so the car was running without the MAF, and everything seems fine, but as soon as I connected them back up it was pulling again like it was about to stall while pulling off/building speed up, It does this at hot or cold engine.



Im guessing water has somehow got into the MAFAM, but when I opened it up it seems fine, I cant see any damage or corrosion to the contacts anywhere, and the case is almost watertight!



I've set it to the correct settings for the Pierburgh but it doesnt seem to change.. (I've been running this setup for months with no problems)



I did bring the MAFAM inside and put it in a warm room to dry out to see if it had any moisture in, and opened the airbox and checked the MAF and filter for any water that might of got sucked up.... filter is dry and MAF seems okay...



I connected everything up again and went for a drive for 20 minutes everything was fine, however the next morning it had gone back to rough running again.



So I unplugged the MAF again and its all good.. apart from the hardly any power which comes with running no maf



My obvious guess is the mafam somehow got moisture in and has been damaged but Im not 100% sure if it could be the ECU or Injectors at fault.



If anyones got any ideas that would be a great help.

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