My Nissan FB 14 has a GA 15 (DE) engine

Hi Buddy, my son has the same car and these are the things I have done to his, it gets 14.5 km/litre and has done 164000km. Do the basic tune up plugs air filter, replace the pcv valve in the cam cover, check to see if oil is leaking out the bottom of the distributor onto the auto bell housing (they all do) if so strip and rebuild the distributor with a new bearing and seal, bearing # 6000rs2 and oil seal 12.45x22x6mm nissan part number B2131-01M00. Oil soaks the bits inside the housing and causes problems. About a 1 hour job. And the main one is to remove the thottle body (TB), clean it with carb cleaner. Slice the silicone sealer from around the silver rectanglaur cover and carefully lift off, On the front side of the TB are 3 connections onto the circuit board from the sensors in the TB. Resolder these connections, they workharden with vibriation and dont make contact anymore. This causes rough running and high fuel use. Replace cover and reseal. Remove the 2 screws from the idle valve and remove, carefull to not rip the gasket, and spray clean the carbon from the small rotary valve and then in the passages of the TB, replace. Another cause of high fuel use is the coolant temperature sensor shorting out and causing a full rich signal to the computer. Its located behind the oil filler cap on the back top front of the engine screwed into the inlet manifold, it has a square type 2 pin plug. Easy to replace, quite cheap and a big influence on the tune of the engine and fuel use. All these procedures can be found with GOOGLE and on You tube. Fyi if you have an oil leak at the back of the engine replace the oil pressure sender they all seem to leak too ! Good Luck

Hello, would this also manage to rectify a starting and stalling problem?

Hi Terrance, The stalling starting problem could be caused by a couple of things. If the oil seal has gone in the distributor and its soaked the inside then this will cause problems, easy to rebuild, youtube has several videos, nissan and honda, . A oil stain, puddle under the distributor or wet inside the cap is the big giveaway.
The problem with the throttle body is for FB14 nissans. Most cars of this age here have been modified already as its a common problem, The connections from the sensors in the TB break at the circuit board due to vibration and the computer gets confused and over fuels or doesnt fuel at all. Its a bit more involved to do but no biggie. When you resolder the 3 main connections you can also add a short piece of wire to bridge the joint for extra piece of mind. Cleaning the idle valve helps as this carbons up and jams causing stalling and starting problems.
These cars are getting old now but most of the problems that start to appear are not that major but are enough to stop it from being driven, just work your way thru each one and your be back running in no time. Its best to do all these things as they are all inherent faults in this car.