Hi
I have a 06 1.6 16v 3door stilo
So I reading up on why my car lacks power and struggle to keep a constant idle and when accelarating,it just doesnt move like it use to. When driving at a constant speed,the car would lose power and then come back.

So I tested each coil by removing one at a time while engine running and 3 cylinders work but when removing one of the coils,the car idled the same. No change. Swopped it out with another cylinder and the coil still did not work.

So its then definitely that one coil that needs replacing right?

Thanks guys?

Sounds like it. I would replace all four. Also your engine motif warning light should have come on.

jim cooper said:

Sounds like it. I would replace all four. Also your engine motif warning light should have come on.

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It is on yes

NebulaStilo said:

It is on yes

Click to expand...

After removing the one coil that not working and putting it back because needed to fetch someone at work,the car now misses altogether. Before it would just lack power and idle bad. And poor acceleration but never really misfired. But now it's all of a sudden misfiring altogether.

Then the coil is completely finished right?

Thank you

You will have to change all the coils. They are not too expensive. A coil fails in stages. First you notice a hesitation when accelerating then it gets worse and only 3 cylinders are firing. Also you may have a failure on a second coil.

Also it would be a good idea to change all the four spark plugs together with the new coils - if the plugs weren't changed for years, those can add up to the natural degradation of the coils...

Will diagnosis show the exact problem?thinking of doing diagnostics

Thank you for your help

It should do.

I replaced all 4 plugs already.

I noticed my speedo jumps around and most of the time when it does this,the car looses power or misfires but then corrects itself. The car drives normal after replacing coils and plugs. But i can feel it's just not the same. When pulling away from a traffic light with your foot flat then it feels very lazy. Normally it would pick up quicker and as you flooring the car you can feel hesitations as the car drives through the gears

How can i explain the hesitation?
Say when a car is idling and it drops 250 to 500rpm and then back up to normal and again drops. I think they call it hunting? My stilo idles smooth but does that 'hunting' when driving. Best i can explain it from the other side of the world lol?

Maybe not as much rpm as that but ya on a smaller scale.

If you accelerate slowly through 1600-1800rpm, does the car hesitate a bit?

Is it worse first thing in the morning, when it's stone cold?


If yes, then chances are you need a new lambda (aka "oxygen") sensor.

The other cause of a fluctuating idle is the throttle position sensor could need a clean or reboot.. but if you've been driving with a duff coil for a while, it's more likely that the lambda has been contaminated, so look at that first.

It might appear if you run a diagnostic check.


Ralf S.

It mostly hesitates at higher rpms.
No the car idles smooth in the morning.

Very seldom just after you start the car even when the engine is warm,it will struggle to idle and the car won't rev. It lasts like 5 seconds then I gain control of the throttle again and then all is normal.
Its only on higher revs where the car feels hesitant. Feels laggy. Sometimes it runs and picks up good but other times it can't even take on a bakkie. The car doesn't misfire ,just doesnt pull like it use to.

The idling is fine besides that seldom thing I explained. The speedo jumps down to 0 and back up to speed im traveling at. When it jumps,the car usually drops RPM and power and then almost like it starts to pull like it use to but then lags again. All this is done very subtle. Like if you don't know the car or cars,you wouldn't pick it up

Even the hesitation is very subtle.
When the speedo jumps ,it will lose power and rpm for like a second then it will feel like its going to pull 100% then back to usual lag. I can send a video to you over email but that will only show the cars hesitation because there's no telling when the other stuff is going to happen lol. Mind of its own