THE ISSUE:
My car Toyota Belta 1.3 2SZFE (Mileage 81,000 km) was giving bad fuel economy. It was 9km/l (without AC) whereas it was around 12-14 km/l a few months ago. I had gotten the throttle body serviced back then (a lot of considerable sludge came off then) but after that the fuel economy decreased.
SERVICES PERFORMED TODAY:
Engine was flushed using engine flush oil.
I drained the previous Shell 10W40 and poured in Shell 5W30 API SN GF-5, after flushing.
Engine oil filter was replaced with new.
Air filter was replaced with new.
MAF sensor was cleaned (using contact cleaner)
AFR sensor was cleaned (using degreaser)
Throttle body was cleaned (using carb and injector cleaner)
A lot of dirt came off from MAF, AFR, Throttle Body. (I disconnected the battery terminals before performing these services)
Also, I have ran injector cleaner in fuel tank twice recently after topping up the fuel tank both times.
RESULTS SO FAR:
The car has become responsive, the pick has increased. Before servicing these three parts, the car was power hungry, now it accelerates nicely. Exhaust pressure is also good. I still have to see fuel economy as I would be able to see that after consuming current tank.
QUESTIONS
Question 1) I noticed that there is slight knocking when accelerating from low RPM. On higher RPM, it's alright. What could be the reason?
Question 2) The engine is sounding a slightly different than before. What could be the reason?
Question 3) I haven't done any OBD scan/calibration after performing above mentioned services. What's recommended by you?
Question 4) Are TPS and MAF sensors the same thing? If not then what is the location of TPS Sensor in this car?
Question 5) In coming day or two I will be servicing PCV Valve, Fuel Filters and Catalytic Converter. Any suggestions for that? Anything else besides what I have questioned/mentioned?
