Audi 20v turbo problems


New member
Hertfordshire, WGC
A3 1.8 20V TURBO
Hi, can anybody please help me I have an Audi 1.8t and have just fitted a new boost gauge since doin this I have noticed when I rev it up it is fine but when the revs drop they go really low as if the engine is goin to stall, it will then istantly pick back up and tick over around 900rpm. Thank you
When the battery is disconnected the ECU needs to relearn the engines characteristics, it will be fine again after a couple of hundred miles driving.

Mine did the same thing, lumpy tickover, almost stalling, auto windows didn't work at first, just give it a bit of time and don't worry;)
battery disconnect causes issues.

throttle body being dirty causes the same - check this 1st as the throttle is electronic controlled and also works as an idle valve so if its partially blocked with carbon then it has to adjust itself
PCV system being full of crud also does the same
coilpack could be on its way out

throttle body should be cleaned roughly every 40k. easy enough to do as its only 4 cap screws holding it in place and use some carb cleaner or petrol to remove the carbon. NOTE if its a electronic throttle do not force the butterfly valve as you will damage the stepper motor
have you had a scan done to see if theres any errors other than a low voltage from the battery. not all show on the dash
also on that engine if the problem re occurs then you need to perform a throttle body reset and relearn this can only be done with ross tech or odis ross tech is easily obtained on e bay with the light version which lets you access only one model audi but it will do everything the fuill version of ross tech does

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