If your pod filter made a difference, then your original system must be clogged.
I run a vacuum gauge on the downstream side of my filter, if it reads a slight vacuum then you know it's all sealed up and filtering properly.
No vacuum means you've got a leak.
High vacuum means you've got a blocked filter.
The problem with pod filters is none of them filter worth a damn. Ricers can get away with it, but on a 4wd they can kill your engine in a very short space of time.
I've never bothered with any diesel miracle goo. Never had any problems that I thought one would solve.

[/quote]
KiwiBacon, The paper airfilter on mine was only put on as a temporary measure until I put the Finer Filter cartridge on. The paper element one was only a week old when I put the Finer fiter one on and still the difference was noticeable. It is well known especially at the Nissan Franchised service center that I used that the 92-95 Diesel Auto Terranos had two problems
1 A cooling system that wasn't up to the Job
2 an air supply that was badly positioned and also undersize so engine was starving for air
Even people that have fitted a snorkel have also noticed improvements to the power of the engine for exactly the same reason (air being forced through the filter was supplying more air to the engine).
when you compared the two filters under a low powered microscope the holes in the elements were about the same size but in the Finer Filter there was a lot more of them.
To give an idea of the improvement with the finer filter I could run quite happily all the way up the bombays in overdrive at 100kmph which even with a new paper element I just simply couldn't do.
On top of this was quite a significant cost saving as the last paper element was $48 but probably dearer than that now, the Finer Filter was $125 with two sleeves supplied I had the FF on the vehicle until I recently sold it (6 years) washed and changed sleeves every month. You don't have to be a rocket scientist to work out it was pretty good value for money.
I honestly don't know how increased airflow is going to kill an engine?