Fault Code PO3OO Mulitple Misfire

[jpspeed]

Fault Code PO3OO Mulitple Misfire on my chevy kalos sport. Ht leads and plugs replaced, new coil pack and lambda sensor tested and working yet it still happens, usually when cold and when you load the engine. any ideas please?

[Hymie]

Are you getting misfiring, or only the engine warning light - with fault code?

If you cannot detect engine misfire – then the OBD is likely to be reporting a fault in error.

Apparently it is not unusual for cars’ OBD to report misleading faults – the information supplied by a scanner reading OBD fault codes should always be treated with suspicion, where everything seems OK.

[jpspeed]

its misfiring and throwing up the engine management light which will flash then go off when the misfiring stops....

[chas2008]

cam sensor, crank sensor ? always a possibility

[TWR]

Hi, you may think this a silly comment but try it, when dark in a darkened area lift the bonnet up & see if you can see the Electrics tracking ( Shorting) within your system, is the plug to your ECU tight? remove it & spray WD40 at the connection pins.

[TWR]

Hi again, I should have said with the engine running.

[Hymie]

The clue here is that the problem usually happens when cold (could well be dampness effecting the electrics/HT system) – TWR may well be correct. I would give the HT leads & coil a liberal spray with WD40, and see if the problem goes away. Take care not to spray surfaces on which lubricant would be bad (e.g. cam belt pulleys etc).

Avoid taking the car to your local garage to fix the problem – unless you make it clear to them that should they replace something which does not rectify the fault, you will not pay for the parts or labour. Strangely few garages will accept the repair on these terms – unless you agree to them replacing everything, including the engine.

[jpspeed]

i will try the lubricant but if that doesnt what what do i do, i have to use the local garage as i'm not a mechanic

[jpspeed]

when you say spray the leads do i disconnect and spray the connections to the plug etc...

[jpspeed]

been told cam and crank sensors would not be imtermittant misfire. Its been suggested it could be the nfuel pump. tried everything else on here, still the same

[TWR]

Hi, open your bonnet, fire the WD40 in the direction of the leads, regards the ECU Plug it looks like your SCARR lead ( If you have one) at the back of your TV, the lead should be a tight fit but try what has been suggested but take the HT leads off at the TIP ONLY, did this problem start after you changed what you have stated?

[jpspeed]

it was a sticking valve, thanks for ur help!