Valver - mis-firing early in the morning

[cliokiz]

Basically, the story so far is, on some mornings, my valver will misfire slightly, when it's particularly cold out, but when i give it some slight revs to warm it up it soon sorts it out and i can happily drive to work with no further problems.

This morning though, it was quite bad. Started her up and she sounded quite rough as if she just couldn't be bothered, and immediately i noticed there was quite a significant misfire. Not sure whether it was 2 cylinders or just one but it was rocking the car quite a bit. Anyway, gave it some revs for a minute or so to warm up then eventually the engine was running normally again, so i then drove to work without any further problems.

Just wondering what might be causing this?

Recently i've had brand new spark plugs, new leads, new dizzy cap, new rotor arm, and a full service, the only thing i haven't changed is the coil pack (if that's what it's called - the thing on the right hand side of the engine)

Could this be on its way out? Expensive to replace? etc.

Cheers for any suggestions

 

[RSTuning]

Were the leads OE or aftermarket?

When i first read i thought mayby dizzy but u have changed it!

I doubt the rennix/coil will be the one to blame as usually it wouldn't run at all.

Paul

 

[cliokiz]

I bought them from Halfords , they weren't the Bosch ones, just the cheap alternative, Halfords own brand i think, could these be the problem?

 

[Matty]

I would look at coolant temp sensor (£10 from GSF) and also the Idle Control Valve which you can clean with carb cleaner.

I did all you have done on mine and still I had intermittent problems. Now all gone touch wood.

Lambda is also a sensor worth changing if you have done over 100k.

 

[Matty]

http://www.williamsclio.co.uk/forum/viewtopic.php?t=8576 is worth checking

 

[cliokiz]

Cheers for posting that! Some very good suggestions.

Wondering if it could be the Coolant Temp Sensor or ISCV..

I'll find some guides on how to check those and wait until i've got some days off work to have a look.

 

[White16valver]

Mine does this too! I just call it 'character'... LOL

 

[Matty]

The coolant temp sensor is actually a sensor that feeds the injectors dependent on temperture, so could be that.

ISCV is bound to be coked up. Both are simply jobs that anyone can do themselves.

If changing the coolant sensor, thread new one in by hand as it is brass/copper and soft. If you use a socket it just seems to turn and turn until the head snaps off. That happened to me.

Do all the service items too. I find car always runs better when oil is changed. Forte additives are good at cleaning injectors, fuel system etc. Use them every 6k on mine and would prefer to do that and use Sainsburys SUL than use Optimax.