Been some time since you asked this question, but what the heck. How many kilometres have you got on the vehicle? Being now 5 or 6 year old I'm guessing probably something like 100,000 k's at least. So regardless, time for a intake manifold clean, new glow plugs and injectors. Common rail injectors have a MUCH harsher life than the 'old school' mechanical ones. All jobs that a competent person can do themselves, other than recoding the replacement injector calibration codes into the ECU (unless you have a professional grade scan tool). Just take a picture of the codes (on the top of each injector) and record which cylinder the injector was fitted, and then take it somewhere that has a suitable scan tool to do it when the job is finished e.g. diesel shop, auto-electrician.
If the cost of this task freaks you out, think what a replacement engine (due to oil starvation) will cost if you do have an uncorrected problem. To monitor for problems caused by leaking common rail injectors the oil pickup screen should be routinely inspected each oil change (just via a borescope up the oil drain plug hole), and you can bet the Toyota service department isn't doing that.