[Rocky833]

So I have a Civic 1.4 type S and I hadn't noticed this when buying the car as the test drive wasn't very long. But once the engine is nice and warmed up, everytime I come to a red light and stop, the car reaches it's normal idle, but then just drops to about 500rpm before catching itself back up to it's normal idle. This has been really bugging me as I am unsure what it is and the fact that it doesn't happen everytime. The car feels like it's about to shut off essentially, but doesn't.

Also I'm not sure if this is normal but when I'm in 6th gear and doing 40mph, the revs sit at about 1900-2000rpm and this wasn't the case with my previous car. Although I'm not sure if this is because the other car had a much larger engine being a 2.0L BMW.

Also when first purchasing the vehicle and filling up a tank of fuel, and resetting the trip, I was getting terrible fuel mileage, I was averaging 21.5MPG and I got through half a tank of fuel only covering 120miles.

After having a full service the MPG has gone up to 26, but I feel this might be normal seen as I use the car for very short journeys, and the fuel needle has barely dropped after covering 50miles.

So if anyone has any knowledge or understanding of what I'm experiencing, I'd love to know what the issue could be.

 

[eagle123]

When has it last been serviced? It looks like it needs air filter spark plugs and have the coil packs checked and replaced, as well as the oil and filter change.

As for fuel economy if u doing short runs in the cold that is to be expected but check your tyre pressure this has a affect.


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[Rocky833]

When has it last been serviced? It looks like it needs air filter spark plugs and have the coil packs checked and replaced, as well as the oil and filter change.

As for fuel economy if u doing short runs in the cold that is to be expected but check your tyre pressure this has a affect.


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It was serviced a few weeks ago, so new engine oil + filter, new air filter. As it was done by Kwik fit, they don't include spark plugs, although they do add on the report the condition of them and it was given an Amber rating meaning they are okay but could do with changing soon. And tyre pressure is at 30 as recommend by manufacturer. And tyre condition is also good according to the report carried out by Kwik fit.

 

[Diddles1987]

Sounds like a vacuum leak. I doubt quick fit checked your spark plugs to give them a rating.

 

[Rocky833]

Sounds like a vacuum leak.

Sorry if this is a silly question, but where may I be able to find this and could it be resolved at home?

 

[Diddles1987]

With the engine running you could spray brake cleaner around the vacuum lines etc, if it sucks any in through a vacuum leak the engine rpm will raise.

Maybe they have left something loose around the air filter area, as any unmetered air coming in after the MAF sensor could cause your symptoms.

 

[Rocky833]

Sounds like a vacuum leak. I doubt quick fit checked your spark plugs to give them a rating.

I just searched online signs of a vacuum leak and the main one was a hissing sound coming when the cars running, however I have ran the engine several times with the bonnet up, and all I hear is the sound of the motor, no hissing....

 

[Rocky833]

With the engine running you could spray brake cleaner around the vacuum lines etc, if it sucks any in through a vacuum leak the engine rpm will raise.

Maybe they have left something loose around the air filter area, as any unmetered air coming in after the MAF sensor could cause your symptoms.

Also, would a vacuum leak come up as an error code? Because they ran a check for codes and the car was clean. And I've been experiencing this before the service, having the service actually made it better as it occurs much less frequently

 

[eagle123]

Still i would change the spark plugs and also check coil packs.
If they chsnged the air filter check all is securely fit and maf sensor plugged in
I would have used genuine honda parts as they are more suited to your car.


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[Diddles1987]

It could come up as a code, sorry but I've only been a honda owner for a few months and not had any experience with your engine so cant be any more help I'm afraid.

A dirty/sticky throttle body could cause issues to.
You could also try disconnecting the earth lead on the battery for 5-10 minutes and reconnecting just to see if it helps, easy to do and no harm in trying.

 

[Rocky833]

Still i would change the spark plugs and also check coil packs.
If they chsnged the air filter check all is securely fit and maf sensor plugged in
I would have used genuine honda parts as they are more suited to your car.


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How much is a spark plug and coil pack change estimated to cost? I've only owned 1 car before and the coil pack was £150 as it was a BMW

 

[Rocky833]

It could come up as a code, sorry but I've only been a honda owner for a few months and not had any experience with your engine so cant be any more help I'm afraid.

A dirty/sticky throttle body could cause issues to.
You could also try disconnecting the earth lead on the battery for 5-10 minutes and reconnecting just to see if it helps, easy to do and no harm in trying.

I have had a look at throttle body cleaning but I know other people have had issues worsening with idle, whilst some say a simple clean is all that's needed. No re calibration required.

I did have a new battery installed a week ago, so maybe that would work towards the solution you just offered

 

[eagle123]

Just check on eurocar parts mister auto or aurodoc
If the revs are falling it looks to me a leak in the rubber connectors just check all the hoses are tight.
Also examine for cracks and check all connectors are secure.


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