Vauxhall Astra intermitent misfire cylinder 1

Car: Vauxhall Astra
Variant: 1.4ls
Model Year: 2004
Categories: Running Rough, Starting & Power Loss
my car has developed a misfire the fault code is po301 which is misfire in cylinder 1. it seems to misfire under load up hill when the engine is starting to heat up. it will usually go away when the engine is hot most times the eml will come on. if i stop the car with the eml on and misfiring and start it again the car will run perfect with the eml on. i have changed the coil pack, plugs put injector cleaner through it. all parts have been new. it doesn't have an egr valve the car has done 57000 mls. i change the oil and filter every 6 months. please help its driving me mad!
Posted: Nov 25, 2011 (12 years ago)
Sounds like your aproach is good,problem now is eqipment,guessing you dont have a 'scope.so you'll have to do it the hard way.
If you cant affect a fault can you move it?,by that I mean swap #1injector for #2 injector,has the miss now moved to #2 ?
if so you have a faulty injector,now in #2 's position.
if no change the either you have a wiring fault to #1 injector/harness or one of the injector drivers in the ecu as bought it.
So,swap over injectors and try,while your doing this pay close attention to the injector seal,may be its damaged and sucking air.
Posted Nov 25, 2011 (12 years ago)
Could also check wiring to coil pack .
Posted Nov 25, 2011 (12 years ago)
should I change the fuel filter first before the injectors. does anybody know if changing the injectors over is a big job. when i put forte injector cleaner through it, it ran fine for 2 months then came back, maybe it needs more cleaner through it. any help would be appreciated!! thanks
Posted Nov 26, 2011 (12 years ago)
hi i have a similar problem, well i think and i need some help, ive also got a astra g 1.4 ls and everytime i have my foot down its a bit sluggish and the rev counter loses power and my car rocks back and faward and thats in all gears roughly above 3k revs any ideas why guys? and another problem, everytime my cars stationary while turned on, when i rev the engine 2 about 2k revs and let the gas go, the engine makes a knocking noise when it idles back down just below 1k. any answers will be apreciated cheers. dee
Posted Dec 12, 2011 (12 years ago)
Sorry i posted this on the wrong thread but please help if you can cheers
Posted Dec 12, 2011 (12 years ago)

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