"Electrical was the first one," said Cox. "Somewhere in our wiring into the computer that makes the car rev which led to the car driving itself and also the car cut out a couple of times.
"The thing that cost the time was midway through a stage the car shut off for two minutes and, while the clock was ticking, we had to park at the side of the stage and we lost two minutes because of that.
"The other problem we could keep in control, but when it cut out, we really couldn't do anything about it."
It was a different issue on day two.
"We had boost pump problems where all the silica hoses would fill up with oil and they'd be popping off in the stages so we kept losing power."
On problem-free stages, though, Cox was pleased with the team's performance.
"On the second lot of stages on Sunday we got a fourth fastest time and then a sixth fastest, but had an overshoot at a junction, then we did another fourth fastest time.
"The final stage was probably one of our best stages, 'til the boost pump popped off again. But we got our split times and they showed that at one point we were second fastest and at another we were fourth - so it shows we were at the top when we were going well.
"I've got a new co-driver running with me and for the first time I'm running my own written notes, and on the Sunday afternoon together we were working real well."
Work on the car over the summer had improved performance and addressed the issues of last season, making it doubly frustrating that new problems arose.
"We had a big overheating problem last year so we put new radiators in, new oil coolers in, new ducting for the air flow, things like that, so we thought we had the car nailed, only to find we had more problems which is quite frustrating."
There is a relatively short turnaround time ahead of the second event of the series - the International Rally of Whangarei on April 29-May 1.
One compensation is that there is very little damage to the car from Otago, so efforts can be focused on finding the source of the weekend's problems.
World Rally Championship driver Hayden Paddon dominated the Otago rally, winning with an eventual record margin of 9 minutes 22.1 seconds.