hunting for revs and missing c20xe coil pack

[cavsri93]

To start with i bought the car about 2 months ago and it had a idle hunting problem and a slight miss. I just thought it would be the icv or a blocked breather. So when I got the car home I cleaned the breathers out and put a 2nd hand but fully working icv on it and it was still hunting and missing after about 4 days the car lost nearly all its power and we found that the catalytic converter had collapsed and was blocking the exhaust we cleaned the exhaust out and it seemed to run a lot better but it's still missing and hunting on idle I've changed the maf, cts (bosch) tps (bosch) new leads and plugs new crank position sensor. When I've done the paper clip test it doesn't come up with any faults I've tried disconnecting the battery overnight. It hesitates quite bad but after about 4 or 5 thousand revs it goes really well. I don't know if this is related but sometimes when coming round roundabouts the car loses power as if it's not getting any fuel ? The car is a cavalier c20xe coil pack. Any help or suggestions are much appreciated Thanks.

[Cavalier342]

Lambda sensor?

[cavsri93]

I'm going to try that next. it's just when I unplug it the eml comes on so I figured it was working but il replace it any way cheers

[planetc]

I'd hazard a guess on over fueling. Might be worth checking the fuel pressure.

[Robsey]

Definitely sounds like a mixture issue...

[cavsri93]

Thanks for the help people. I have now changed the lambda, I couldn't get a Bosch one so I got a ngk one supposedly just as good ? I changed the ignition coil and fuel pressure regulator still no different on idle but the car now feels a lot more responsive and less sluggish I have already got a new inlet manifold gasket and I'm waiting for a new throttle body gasket to be delivered as soon as I put them on the car il update to let everyone know if that cures the problem. Also what's the chances of an ecu on a c20xe coil pack going bad ? Is it a common thing or rarely heard of cheers.

[Robsey]

As long as your ecu has not got damp due to its location low down on the drivers kick panel, then it should be quite reliable.

[cavsri93]

After looking through all the breathers again I've found one that appears blocked. It's the smallest pipe that comes off the top of the rocker cover. It leads down to the throttle bodie and has coolant pipes attached as well is it supposed to be open or is it some how heat activated off the coolant pipes ? I've tried looking all over the Internet for answers and my Haynes manual and I can't find nothing that says if it should be open or closed once again any help very much appreciated thanks

[cavsri93]

Just thought I'd update to let people know I've narrowed the hunting down as I've now changed every sensor apart from air temperature sensor I also found a couple of wires that were melted together in the loom but looking through the Haynes manual it seems it was the under bonnet light and part of the dash lights I've now installed a fuel computer out of a senator 3.0 my friend broke the other day I just need the switch for it I've seen them on ebay so it get one soon. I'm going to take the smallest breather pipe off the rocker cover. Down at the throttle body where the union is I'm going to drill it to 2mm and that should get rid of the rough idle hopefully. I've looked Into the c20xe and it seems quite common for the little breather to block at the union il update once done and let everyone know if this fixes it. I can't believe how fit the engine feels with all sensors changed oil change and all filters changed.