I agree with Haydn, glow plugs are 90% the cause. I am also replacing mine in about 2 weeks. Come winter time they show their true working condition.
Just be ready for the big shocker, I bought mine last month from Midas and they cost R449 EACH, almost R2000 for the four glow plugs.
What I usualy do when my glow plugs is shot and just before I change them is to add some Spanjaart Injector Cleaner to a full tank and only when tank is driven completely empty I change the glow plugs. Reason being that I have found that Injector Cleaner is not good for glow plugs.
Some members have different views on additives, but this works for me and it helps to improve fuel consumption.
BTW, the glow plugs you want to get are NGK CY-55, ceramic coated tip. They will last you a very long time. Don't go cheap, not worth it.
2012 Ford Ranger 3.2tdci DC 4x4 Auto aka "Fytjie"
Opposite Lock Bumper; 330w & 480w Phillips 4D LED Lightbars; Phillips HID Headlights; Ford Snorkel; 63mm SS Free Flow; De-Cat; EGR Blanking Plate; Cobra Suspension, Load Hogs, 50mm Mikem Extended Shackles, 8mm Teflon Spacers; Custom Leisure Tech alu Canopy; Rear View Camera; Escape Gear Seat Covers
Everything Works Better When It Is Properly Maintained!