V6 Misfire

[AndyH]

I wonder if anyone could help with my Misfire problem!

 

I have a 99 V6 GhiaX. It normally runs fine - thirsty - but fine. lately i have been experiencing an intermittent fault where it misfires badly, no power, sounds awful and fuel consumption goes through the roof.

 

I first had this problem about 10 months ago, my local garage said it was a faulty Coil Pack. We replaced this but to no avail. after several weeks of tinkering and swapping coilpacks (back to the original) the problem went away, and i had no problems over the winter.

 

But now the problem has returned, its not all the time - but most of it.

 

Any ideas would be very helpful.

 

Thanks

[sepulchrave]

HT leads are the number one culprits of this kind of problem followed by the coil pack and the spark plugs themselves, ideally you should replace the lot, Iridium plugs are excellent and really do last much longer than the standard.

 

If your fuel consumption is truly abysmal (i.e. 25 mpg is impossible to achieve) then look to replace the lambda probe, the MAF element and the blue temperature sensor on the thermostat housing.

[AndyH]

HT leads are the number one culprits of this kind of problem followed by the coil pack and the spark plugs themselves, ideally you should replace the lot, Iridium plugs are excellent and really do last much longer than the standard.

 

If your fuel consumption is truly abysmal (i.e. 25 mpg is impossible to achieve) then look to replace the lambda probe, the MAF element and the blue temperature sensor on the thermostat housing.

 

Thanks for the advice.

Car is a V reg 2.8 Manual GhiaX and has done 75000. I had the plugs and leads changed about twelve months ago before we decided the coil pack needed changing.

Fuel consumption is somewhere between 10-15 mpg. What/where are the sensors you mentioned. Especially the temperature sensor. I did think it may be something to do with the temp - during the winter it work okay, now its starting to warm up, its misfiring again, and occasionally stalling when I slow at junctions.

 

Would connecting a diagnostic to it tell me the problem?

 

Thanks

[cyborg]

I would try lambada first

 

some wd40 on the wires connecting the lambada senser might do trick or new probe ,you can test them with voltmeter.

 

the lambda goes into cat.To locate you follow drivers passenger side door piller underneath car you will see some wires comming out exhaust the connection block do a wiggle test

 

good luck

 

kev

[AndyH]

I would try lambada first

 

some wd40 on the wires connecting the lambada senser might do trick or new probe ,you can test them with voltmeter.

 

the lambda goes into cat.To locate you follow drivers passenger side door piller underneath car you will see some wires comming out exhaust the connection block do a wiggle test

 

good luck

 

kev

 

What are the readings i would expect on the Voltmeter?

 

Andy

[sepulchrave]

Look, all these parts are cheap compared to the fuel you're burning, replace the lot,

[AndyH]

Look, all these parts are cheap compared to the fuel you're burning, replace the lot,