Muir had a hard act to follow but did a fine job in his first year by finishing second in the NPC.
But things fell apart in 1989 when players either left the Capital or retired, and Wellington slumped to seventh after finishing second, first and second in the previous three years.
Muir came on to the scene with big success with his Wellington Club in the previous few seasons. He took over a Wellington team in 1988 which had won 19 of its past 20 NPC matches, but early indications were not great with big losses to Queensland and Auckland (58-0) in the South Pacific championship.
But there were reasons for this. Auckland was pretty much the winning Rugby World Cup team, but Wellington was without the complete front row, one lock, outstanding flanker Dirk Williams and a No 8 from the previous year. So the side was hammered.
Muir could have used former All Black hooker Hika Reid and outstanding big former Manawatu No 8 Emosi Koloto in these games but he had reasons for leaving them out.
"I wanted then to show their commitment to Wellington by playing club, rather than show other club players that anyone could march straight in and take a spot," Muir said.
It worked. When Williams returned later in the season to join Koloto and Mark Hudson in the loose forwards, and Reid, Murray Pierce, Marc Verhoeven etc in the tight, Wellington had the base to fire rockets.
Just two matches were lost, an epic against Auckland on a glorious day in Wellington where the 58-0 from the South Pacific was turned around to a 12-17 loss. And it was closer than that.
But the big mistake was a few days earlier, when Wellington stopped off at the Wairewa Hot Springs north of Auckland to prepare for a match with North Harbour just 48 hours later.
"We decided to have some R and R there," Muir said. "But some of the boys didn't read the signs properly and came down the Black Hole head-first. So we ended-up with three of them cut. It wasn't great from my point-of-view because I had just taken over as CEO at the New Zealand Water Safety Council."
The injured players were key back John Gallagher, halfback Tracy Smith and centre Denis Tocker. With them below par, Wellington lost 15-20 to North Harbour. But the team ended the season with a mass of wins.
Come 1989 and there were problems that Muir conceded he struggled to come to grips with. Koloto was overseas playing rugby league, prop Brian McGrattan retired before the NPC started, Hika Reid struggled with injury and Dirk Williams also left.
To add to the problem a below par Wellington senior competition meant there were too many teams and therefore easy matches, good players didn't have to exert themselves, and as a result their fitness levels were well down when Muir took them over.
So the early northern trip was a disaster, with heavy defeats by Waikato and North Auckland, and the side struggled right through, ending with heavy losses to Canterbury and Auckland.
Worst of all, he says he took too much time to sort the loose forward problem out.
But he still put his name up for another crack at the end of the season - only to be beaten by Andy Leslie.
Muir was disappointed but philosophical.
"It's one of those things you go through and you learn a lot. You don't always learn from good seasons - you learn from the other years. And I thought I had learnt a lot, and there was the potential to put in place (in 1990) what I had learnt. So I put the name forward."
But Leslie won, and Muir went back to club rugby and contended himself with the age-group grades.
"As a coach you have to take the responsibility yourself But at the time you deal with the facts as you see them at that time. So hindsight is brilliant."