Engine trembles and Vibrates before Shuting down

[Happily1986]

Not dieseling. The trembling is before I shut off the engine.

Here is how it goes. Park my car, put the Gear into 'P'

turn off the A/C and the rev falls and engine trembles.

Then moments later, the Rev builds up again to save the

stalling engine and I shut off the engine.

 

Everything is fine when I turn off the engine while Gear is

in 'N' or 'D'. But nobody will shut down engine when in Gear

right. This will cause Premature failure to the GB.

 

Alot of possibilities bro even vacuum leak is a probable cause. Suggest you go back to Kah Motor and run through their diagnostics to diagnose properly the problem. I shouldn't think you are obligated at that point in time to go for rectifications with them. Better than go in blind, change this change that, no end. Lucky if you hit the right component. Unlucky, you spend a bomb changing this and that in your quest for random troubleshooting.

[Chickensoup]

Not dieseling. The trembling is before I shut off the engine.

Here is how it goes. Park my car, put the Gear into 'P'

turn off the A/C and the rev falls and engine trembles.

Then moments later, the Rev builds up again to save the

stalling engine and I shut off the engine.

 

Everything is fine when I turn off the engine while Gear is

in 'N' or 'D'. But nobody will shut down engine when in Gear

right. This will cause Premature failure to the GB.

 

For Autogear box "P" or "N" is same because it is free gear (Neutral), only "P" has a transmission lock. If it only happens on "P" and not on "N" it is really very strange.

 

Have you tried to get your workshop to clean the throttle body? There could be some dirt built up around the throttle body butterfly that cause this problem. The mechanic will spray STP Carb Cleaner to clean up this dirt.

[5936]

Pop in a bottle of redline fuel injector cleaner and let it run through a tank of fuel.

It may help clean up injectors.

And consider cleaning throttle throat body, with a carb cleaner spray.

Thewe are the cheapest and obvious first aid remedies.

[Chickensoup]

Good suggestion

[Dezouk]

Faulty air flow sensor or idling valve or map sensor?

[Blue850r]

Is Air flow sensor = MAP sensor ?

[Gnahp]

Is Air flow sensor = MAP sensor ?

 

No. But they are the component that used to determine the air volume suck in by the engine using different methods.

 

[Blue850r]

Does both exist in one engine or it is either MAP or Air Flow sensor ?

[Gnahp]

As far as I know, it is either MAP or Air Flow Sensor

[BoneStock]

Is Air flow sensor = MAP sensor ?

 

no air flow is measured by MAF = mass air flow

 

air pressure is measured by MAP = manifold air pressure

[kqkhlj]

what is the best way to clean the sensors??

[5936]

Electronic contact cleaner in spray aerosol can

[Gnahp]

If your air flow sensor is those hot wire type (very likely), make sure the cleaner is residual free and plastic friendly.

[Godfinger]

I just pop in a bot of Fuel injector cleaner

From Redline. So far only 1 occurance

After driving 130km with the injector

Cleaner. Hopefully, the occurance rate

Will drop to zero. Next week, will be

Planning to do a TB clean.

[Godfinger]

Ruling out every possible fault one

By one. Waiting for TB clean next week

Before going on to the sensors and

ICV.

[Blue850r]

Very wise step by step analysis. I have known 2 friends driving yr model. Both are into their 8th or 9th year. mileage approaching 300,000kms. Engine and GB still healthy. They are those who seldom service their car type of motorist. This car model can take a lot of abuse.

[Yuan]

I just pop in a bot of Fuel injector cleaner

From Redline. So far only 1 occurance

After driving 130km with the injector

Cleaner. Hopefully, the occurance rate

Will drop to zero. Next week, will be

Planning to do a TB clean.

 

In my opinion, it might be a case of dirty TB.

 

And aftermarket air intake are usually the causes of dirty TB.

 

However, even for stock intake, cleaning of TB after a long mileage like yours may be helpful. There will also be dirt trapped in the TB.

[Godfinger]

Just did TB cleaning this afternoon by spraying cab cleaner directly

Into the butterfly. Though not a very thorough job, hopefully

Can clean the TB abit. Still monitoring the situation and will

Be going to workshop for diagonise if the problem still come back