07-04-2019, 09:52 PM
I'd check for a vacuum leak first. After that ICV and MAP are candidates. The info on here for testing sensors (power supply to them & sensor itself) is also applicable to your car. http://www.306gti6.com/forum/showthread.php?id=80340. Even if you test the voltage on the wiring though that isn't a guarantee the wire can carry a load & allow the ECU to have control / receive signals. It may be cheaper in the long run to get a diagnosis from good garage.
If you decide to sort it yourself & go down the road of replacing the MAP and/or ICV, whatever you do don't go for the really cheap one off eBay. They probably won't work properly & might send you down a diagnostic blind alley. Your cab is a Phase 2 isn't it? If so …
MAP - Pug number 1920.9H, Bosch 0 261 230 012
ICV - Pug number 1920.X9, Magneti Marelli 820003385010, VDO C95197
If you decide to sort it yourself & go down the road of replacing the MAP and/or ICV, whatever you do don't go for the really cheap one off eBay. They probably won't work properly & might send you down a diagnostic blind alley. Your cab is a Phase 2 isn't it? If so …
MAP - Pug number 1920.9H, Bosch 0 261 230 012
ICV - Pug number 1920.X9, Magneti Marelli 820003385010, VDO C95197