RB20DEt is a very tough engine, in stock form you should get relatively good mileage. Manual has better consumption compared to auto but if you do not keep the engine in check e.g plugs,air filter, fuel filter, oil, etc then consumption may go up.
Common problems with the o2 sensor, AFM and generally the contacts get oxidised so best to use contact point cleaner on all electronic connectors. Also re doing your grounding may improve the voltage and reading to the ecu.
Simple upgrades from bone stock is the RB25 stock turbine, changing the down pipe and improve the exhaust system.
tt48... oil capacity should'nt be 4 litres, was the oil filtered removed as well?
Check if your oil sump bengkok in already...if yes then it will cause the dip stick reading to be wrong.
Cheers!
Common problems with the o2 sensor, AFM and generally the contacts get oxidised so best to use contact point cleaner on all electronic connectors. Also re doing your grounding may improve the voltage and reading to the ecu.
Simple upgrades from bone stock is the RB25 stock turbine, changing the down pipe and improve the exhaust system.
tt48... oil capacity should'nt be 4 litres, was the oil filtered removed as well?
Check if your oil sump bengkok in already...if yes then it will cause the dip stick reading to be wrong.
Cheers!