v6 missfiring

[cooltom31]

my v6 is running like crap, its miss firing on cylinders 3 and 4 ive changed the plugs and leads and just fitted a new coilpack and its still doing it. sometimes it will run normally then run like crap for a bit then go normal again. it started out it would hardly ever do it and its got worse. also what does a kknock sensor do? any ideas would be good:thumb:

cheers

tom

[Southie]

Knock sensor = CLICKY (http://www.topbuzz.co.uk/info/knock_sensor/knock_sensor.htm) :thumb:

[cooltom31]

does anyone know where the knock sensor is located on the v6 engines? im thinking space to get in might be a problem.

[Sloth]

there is 1 per bank, one at the front and one at the back.

[cooltom31]

would it be easier to get to it from under the car?

[Sloth]

yes, but still a battle....

[cooltom31]

found the knock sensor and the wire was snapped. so re connected it and still the same problem. if i disconnect the battery to reset the ecu it runs fine for a few mins aswell, then goes back to misfiring when the light comes on on the dash? its even got me thinking about breaking the car now im getting sick. anyone have any ideas? also the diagnostic machine brought up 'rpm signal' does anyone know what this means?

[cooltom31]

i see rpm signal is crankshaft sensor? anyone know where this is located?

[MadamVectra]

on my Vectra V6 it had a habit of the EGR valve going tits up
would run like crap and missfire.
so worth checking that.

[Lee]

Crank sensor is on the front of the block near the gearbox. If its missing on 3 and 4 i doubt it will be the knock sensors as they are on seperate banks.

[cooltom31]

aparently if the knock sensors have a fault the ecu goes into a type of safe mode and advances the timing, i thought maybe thats why it was running like this but musnt be the case.