Toyota premio idle rpm dropping

[Premio]

Toyota premio 260(2010 model)(1500cc, 52K km) idle rpm started dropping , noted high vibration during that time and again reaching normal rpm(600). This happens slow acceleration after running the vehicle in constant speed,vehicle use to accelerate jurky. This doesn't happen often. Fuel tank used to maintain always above 25% always, 95 octain.Engine never stopped and no abnormal sounds.Smooth .

Due to this trouble all 4 spark plugs changed.Air filter changed.but nothing changed.

Fuel consumption in traffic with AC maximum 9km/L  .  Long trips 13~14km/L max. Highway 15~16km/L with slow acceleration Average 80km/h.

Injector(worth fuel system) cleaner added and nothing changed.

Petrol filter with pump removed and cleaned using petrol.Some mud removed from net type filter. After fitting back idle rpm slightly increased and respond to AC cutting in/out increased, after some time rpm started dropping and situation became worst,rpm dropped to 450 , but itself picking up to 600,respond to demand inproved.

Then throttle body cleaned and trip computer was resetting done by a professional. Everything cam back to normal. City fuel consumption 13km/L (never seen before) with A/C, Highways 20~21km/l average speed 80km. 

After few days fuel consumption dropped to 9 km/l in city and highway 14km/L. 

RPM started dropping as before again in idle. But not feeling jurky acceleration!

The doubt i have is fuel filter.

Have anyone face clogging of petrol filter? 

Is it need changing after 7-8 years usage?

Thai filter eliment and pump available for Rs. 4750/=, have anyone used this.

There is no problem in injectors and electrical system.Air filter also in good condition.

Can petrol filter create such condition ?

Do Share your experience if you have gone through similar problem !

[Rumesh88]

If not done already get following things checked.

1. PCV valve 

2. OCV filter 

3. Injector washers for possible cracks.

[Premio]

Only one thing said during throttle body cleaning, injectors closing bit slow! But he said it's not a problem.

What is OCV filter? Is it near MAF sensor? 

[Rumesh88]

  On 10/8/2017 at 4:20 PM, Premio said:

Only one thing said during throttle body cleaning, injectors closing bit slow! But he said it's not a problem.

What is OCV filter? Is it near MAF sensor? 

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Oil Control Valve filter. It is located near VVT solenoid and sitting behind a Allen key head. Thins I have mentioned above are just routine check ups but sometimes ignored by the mechanics.

Edit: BTW "injectors closing bit slow" does not make any sense. He must have said that based on a reading of the scanner. 

Edited October 9, 2017 by Rumesh88

[The Stig]

  On 10/8/2017 at 11:50 PM, Rumesh88 said:

 

Edit: BTW "injectors closing bit slow" does not make any sense. He must have said that based on a reading of the scanner. 

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Presume he is talking about "Fuel pulse width"