the d4 engine is very fuel efficient due to its direct injection technology-consumption for a 2litre d4 is almost similar to a 1.5litre normal engine. however,it requires high octane fuel,with a low sulphur content to maintain an ultra-lean burn. now,this is where the catch is. the kind of fuel available locally is nowhere near the quality required to run a d4 engine. and thats where your problems begin with this kind of engine. also,most mechanics are 'afraid' to touch d4 engines coz the setup is different from what they normally handle and thus when you start experiencing problems,you are on your own. the engine is to be found mostly on 2litre cars. service your car diligently and pray!

well,am not very sure about v-power. all i know is that all fuel in kenya is sourced from the same point-kpl depot. the marketers then add some chemicals and sell it as v-power.

I've driven a D4 Premio (the one with the 3S-FSE D4 VVTi engine) for over 2 years with no issues. The key (so far) is taking care of the car. It's not one of those cars you can 'abuse' by postponing service etc. Also,use the right plugs (I have the numbers somewhere).

I also watch where I fuel. That said,I sometimes wonder whether I get the best out of the car especially in light of @wachiras comments on the kind of fuel available.

I've done 13-15.5km/l on the highway which I find impressive. In town it's just about 10km/l (slightly less when i drive aggressively). (Think like going to a place like Voi and back with some fuel left to spare)

Incidentally the technology is not unique to Toyota - the Mitsubishi GDI's,the VW/SKODA/AUDI FSI is more or less the same tech. Read this wikipedia entry for the technical mumbo jumbo if you are interested - http://en.wikipedia.org/wiki/GDI_Engine

I don't know much about the D-4D though only that it's a diesel engine, and I doubt it's directly related to the petrol D4 engine.

Here's some stuff I have managed to find online though:

D-4D actually stands for direct Injection 4 Cylinder Common Rail Diesel Engine. Common rail diesels inject a fine mist of fuel into the engine at very high pressure. The result is the same power and refinement as a petrol engine,but with better fuel efficiency and lower emissions. Toyota D-4D engines are not just noteworthy for their smooth,linear torque,though: that's a characteristic of most modern diesel engines. What D-4Ds are noteworthy for is their unusually high power outputs,equivalent to that of many competitors' similarly-sized petrol engines. The D-4D's rev range is also usefully wider than normal,further enhancing the driving experience.

http://www.thaivisa.com/forum/D4d-t80930.html

D4??!!I cant touch again!i sourced premio 2.0ltr D4 ctv,it didnt reach Nrb..it ceased at Mtito Adei..and towed...the problem was oil!we didnt flash it before topping new and the previous oil had hardened...the worst came when trying to overhaul..no spares..had to import even the chain and some rare bearings..the cylinders were gone and had to be grinded again..luckly after 2months my mechnic revived and has been ok since..may-oct..but it s a power engine,fuel consumptin ok but wen u get similar problem ul never touch it again!