I have a 1999.5 Golf TDI which has sat for quite a few years due to a very slight head gasket leak of compression into cooling system - after I drove it home from San Antonio to Houston some 200 miles I notice a bit of coolant coming out of the overflow on way home and when I asked the PO about it and he said - Oh that's the head gasket we put on - it just needs another one - i am thinking OK now wouldn't that have been nice to know before I purchased it - but I don't call people out I just take it as my responsibility to deal with it since I was the one who bought it - my eyes were bigger than my stomach - lol - ok now for the short story - it is hard to start and when it does it just idles - no above idle speeds throwing three codes 17970 - 16485 - 17656
17970 - Quantity Adjuster ( N146) Upper Limit Reached
(intermittent) 16485 - Mass Air Flow Sensor (G70) Implausible Signal 17656 - Injection Start Regulation Control Deviation
(intermittent) I am wondering since it sat and the non beyond idle RPM happened after it sat - maybe something got gummed up in the injection pump? When I have replaced top injection pump O ring gasket I have noticed a variable type sensor - I think it has to do with IQ settings - would that or something else in the upper two top sections of IP that relates to foot feed input need cleaning?