2006 QP. Intermittent misfire.

Contigo

Contigo

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I think it could be the plugs as said BUT could also be, bad fuel, knock sensor, a clogged air filter, damaged cats, faulty Mass Air Flow Sensor and faulty O2/Lambda sensor.
 
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Elliott653

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TridentTested said:
Ha, mine is booked in there next Tuesday for its annual and MoT (my plugs are due on this service) - I might see yours there :)
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I sincerely hope not! I plan to hang around while Paul checks it out and then take it home with me the same day. (The best laid plans of mice and Maserati owners). :)
 
drewf

drewf

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Elliott, your symptoms are exactly the same as for my QP. It has had new plugs - didn't cure it. New Lambda sensors - didn't cure it. New air filter - well, you get the picture. It's still at Shiltech :(

It will run just fine after a reset, but comes back.
 
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Elliott653

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drewf said:
Elliott, your symptoms are exactly the same as for my QP. It has had new plugs - didn't cure it. New Lambda sensors - didn't cure it. New air filter - well, you get the picture. It's still at Shiltech :(

It will run just fine after a reset, but comes back.
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Hmmmm.

We'd better keep in touch. I had lunch with a mate of mine today. He's an Alfa specialist. His guess was faulty wiring. Hence the intermittent aspect.
 
Ewan

Ewan

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My 06 QP did exactly this on my New Years Eve trip from Dorset to Leicestershire. I ended up stoping as I hate the thought of losing a gamble with a "check engine" warning light! I had it low loaded back to Emblem, who fitted new coil packs. All sorted now. Why muck about with a reset - just replace the faulty one(s) instead and be done with it.
 
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Elliott653

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Ewan said:
My 06 QP did exactly this on my New Years Eve trip from Dorset to Leicestershire. I ended up stoping as I hate the thought of losing a gamble with a "check engine" warning light! I had it low loaded back to Emblem, who fitted new coil packs. All sorted now. Why muck about with a reset - just replace the faulty one(s) instead and be done with it.
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I get that, Ewan and I agree with you. However, last year, it was the number eight cylinder that went. The ignition coil was replaced with a new one and yet once again, number eight cylinder went u/s.
 
Ewan

Ewan

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Oh. Maybe it's not the coil pack! But it still might be, and if the new one has failed that soon, it should be replaced under warranty for free. Worth a go maybe?
 
Gixerboy

Gixerboy

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Elliott said:
Really that simple? Owens didn't mention that.
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The plugs are not "due" to be changed until the 60k mark.
If the plugs are worn, the gap increased & causes higher current draw from the coil to fire the plug. This inturn can lead to a misfire & reduces coil life in the process..
Plugs are a cheap & easy fix & will restore smooth running & idle..

Regards

Dave
 
drewf

drewf

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7,159
Gixerboy said:
The plugs are not "due" to be changed until the 60k mark.
If the plugs are worn, the gap increased & causes higher current draw from the coil to fire the plug. This inturn can lead to a misfire & reduces coil life in the process..
Plugs are a cheap & easy fix & will restore smooth running & idle..

Regards

Dave
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That would be great Dave if it fixed all problems. Didn't make a jot of difference on mine unfortunately, so I'm afraid new plugs won't always fix the issue!
 
Parisien

Parisien

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Why all the speculation.............will hooking it up tell us what we need to know, otherwise just back to the MD way of dealing with things, replace all related parts til it fixes it.......hardly the best method


P
 
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Elliott653

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Parisien said:
Why all the speculation.............will hooking it up tell us what we need to know, otherwise just back to the MD way of dealing with things, replace all related parts til it fixes it.......hardly the best method


P
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Unfortunately, it was a Catch 22 situation for me. I knew from the first time that the misfire happened last year that resetting the codes meant that HR Owen would not be able to read exactly what fault had occurred. However, without a reset, I couldn't get home with the car, other than on the back of an AA truck.

So, McGraths will be presented with a smooth running car and a handwritten report from the AA man, including the readout from his generic fault finding machine.
 
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Elliott653

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Parisien said:
Hoping they diagnose it properly and as important, its a cost effective fix


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I have a warranty with WarrantyWise. To date, they've been absolutely excellent to deal with. They've never quibbled a claim. Though, of course, I hope that it's something cheap and straightforward, like a loose connection.
 
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Elliott653

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1,241
Ok, I'm at McGraths now. Or, rather, I'm in the pub up the road. But, that's by the by. As I feared, their diagnostics showed a blank as the AA man had reset everything.

So, we've decided to change the plugs - which is a three hour job - as a first fix.

Here's hoping.
 
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