Thanks for all the help,. especially Alan Kane for providing the routine to fix it. Thanks also to John Kennard for ringing me. I have tried it the weekend & all seems stable.I reckon the problem was the EGR adaption, but why cleaning the throttle body upset it, I can just guess it's something to do with a change in expected MAP/Atmospheric pressure......................maybe!
Alan suggested:
Warm engine up
reset engine adaptions, by going 01 engine, adaptions, read channel 0, (should show 000), then save, accept save oooto channel 0, exit. Which resets ecu to factory settings.
run throttle adaptions:
Turn the key on but do not start the car.
[Select]
[01 - Engine]
[Measuring Blocks - 08]
Enter Group 060
[Go!]
[Switch to basic settings]
.Leave in basic settings for 10 minutes, even though it says OK. switch back to block groups
exit out.
Turn ignition off for at least 1 min to power down ecu.
Ign on but don't start or touch throttle, leave on for 5 mins, start car & allow to idle for 10 mins wihout touching throttle.
This fixed it,even though I had carried out the procedure before (less the reset to factory settings) many times before.
I do think it was an egr adaption problem.
When saving 00 to engine group 0 in adaptions, it set a 17812 EGR system basic settings not performed code, this then cleared after throttle adaption, or after idling.
I didn't try the routine to reset egr, as it seems to have reset itself, but is shown here:
Most VW/Audi/Seat/Skoda gasoline engines with Exhaust Gas Recirculation (EGR)
Prerequisites (General):
Ignition ON
Engine OFF
Battery voltage at least 11.5 V
[Select]
[01 - Engine]
[Meas. Blocks - 08]
Select Group 074.
[Go!]
MVB 074.1: Min Position in Volts
MVB 074.2: Max Position in Volts
MVB 074.3: Potentiometer voltage
MVB 074.4: Adaption status: (Run/OK/etc)
[Switch to Basic Settings]
MVB 074.4: Adaption status: (Run) then it should change to (ADP OK)
[Switch to Measuring Blocks]
[Close Controller, Go Back - 06]
Special Notes:
For ECU's using ME 7.5, the coolant temp needs to be between 10 and 50 °C.
In case the adaptation fails switch OFF the Ignition for 30 Seconds, then switch it ON and try again.
Retrieved from "http://wiki.ross-tech.com/index.php/Exhaust_Gas_Recirculation_%28EGR%29_Valve_Adaptation"
I am sure when I looked in block 074 before the fix (not knowing what it did) it said error, instead of ADP OK.
John, I think if it had had a reflash at VW, then that would have reset the EGR adaption & fixed it also.
Regards
Steve