From: "Andy" Subject: Zafira 1.6 ecotec misfire Date: 07 June 2004 00:22
Hi first post here so please be nice :-) I have a 1600 ecotec zafira with 20000 miles on the clock, it is driven sedately by my other half and caned by me! The problem is that it has started missing occasionally. It doesnt matter whether the car is hot, cold, under load, or not it will just start to run rough or sound like it is running on 3 cylinders it also loses power when it happens, but it never stalls and there is no error lights on the dashboard I have tried multiple basic fixes but I now need more help on what to do next, So far I have Changed the fuel (from Morrisons to Shell Optimax) Changed oil (10/40) Checked and changed spark plugs checked the air inlet and filter were clean and I have revved the Knackers out of it to ensure it is not a sticky valve
Ensure the coil pack surface is clean- i.e. remove the plastic cover and wipe with a carb cleaner soaked rag. Whip off the HT leads and do the same wiht them- especially over the boots. Re install making sure the electrical connector under the boot engages properly with that on the coil pack. Often the rubber boot prevents it going in all the way[1].
Depress the clip onthe 3 pin on coil pack connector, remove, and check that its not corroded or suffering any other fowl play.
If this is ok, then check all the injector wiring connectors, access isnt good, but it would be best if you could remove each one and examine the connections before putting it back
As the misfire is violent when it happens but intermittent, I would tend to rule out a broken down HT lead, as this would tend to make it misfire all the time. If it continues, suspect either a dodgy coil pack, or a sticking injector on that cylinder.
Tim.. [1] on the HT lead.