Van Duyn recognised his car on the Mobil forecourt and challenged the man driving it, who was well known in Kaikohe for his gang connections.
The driver stood up to him and said he owned the car now.
In the ensuing dispute Van Duyn tried to stab him seven times. Four of those attempts were "semi-successful".
The entire incident was captured on CCTV.
Judge Shortland said aggravating features were that Van Duyn was "drugged up" at the time, "well and truly" addicted to methamphetamine, was carrying a knife in a public place, and tried to stab the other man multiple times.
The only mitigating feature was that he wanted to get his car back. The vehicle was returned by police anyway.
However, Judge Shortland said Van Duyn, who now lives in the Auckland region, should be congratulated for getting himself off methamphetamine without a rehab programme or other outside help.
That was "an extremely difficult thing to do" and staying clean for the 18 months since then was "amazing in the circumstances".
The starting point of five years' jail was reduced for Van Duyn's rehabilitation efforts, attending a Man Alive programme, remorse and guilty plea.
That led to a term of two years which meant the sentence could be converted to 12 months' home detention.