2010 VAUXHALL ZAFIRA 1.6 - FAULT CODE P0303

[linsdav8284]

i had this fault code appear 9 months ago and it was fixed by replacing the spark plugs. However it has just reappeared again yesterday - loss of power and stumbling engine performance. I cleared the fault code , ran it for 100 yards or so and it reappeared. Checked the spark plugs and they are clean so am thinking maybe the coil pack or the EGR valve?. However I have had cylinder misfire problems before which apparently were due to wiring problems in my Prins vsi gas system ( and I was also told by the installer that the wires often break due to the movement of the engine during rough ground travel ???). Any ideas before I take it to the dreaded local Vauxhall dealer garage?

[rich r]

Does the fault reappear if you clear the code then run only on petrol? If so, then it's not likely to be anything to do with your Prins system.

However - Vauxhall coil packs are well known for failing after a while. When was the coil pack last replaced? If you've done 75,000 miles and not replaced it then I would certainly do that. They're not that expensive and very easy to replace yourself.

[linsdav8284]

Does the fault reappear if you clear the code then run only on petrol? If so, then it's not likely to be anything to do with your Prins system.

However - Vauxhall coil packs are well known for failing after a while. When was the coil pack last replaced? If you've done 75,000 miles and not replaced it then I would certainly do that. They're not that expensive and very easy to replace yourself.

thanks Rich. The car has done 55k miles and I have replaced nothing except spark plugs and the usual service items. Yes- the management light reappears irrespective of whether I am on petrol or LPG. If I take it to the Vauxhall dealer for a basic diagnostic check would that give any more info than my iCarsoft i902 OBD fault code reader as to the source of the problem? I phoned them today and they were very woolly as to what the initial £75 check could me - all they said was that they wouldnt trust a 3rd party source - ie my fault code reader. When it comers to trust - I dont trust them from past bitter experience lol of work being done that wasnt necessary.

[rich r]

I'd find another garage - OBD fault codes are OBD fault codes. In fact on some Vauxhall models you can get it to display the fault codes on the dashboard without a reader (certainly could on my 2003 Vectra). £75 would buy you a new coilpack too...