Originally Posted by
ray barker
does it change on all the other cylinders when removing there leads. it could well be a fuel injector get it pluged in it might say what injector or weather its an injector driver fault in the ecu. ive not seen a st for along time see if you can swop injectors around to move the miss fire to another cylinder.no1 is down you say no1 this one should be the timming end if its no1. your not getting 1 and 4 mixed up.its worth putting a brand new plug on that cylinder thats miss fireing plugs arnt as good these days when they get fukered they dont like the cold start fuel. no4 valve looks good by the comp test youve described. have you any symptoms of head gasket problems
pulling the fuse might not be taking the limiter out of the ignition system it could still be intererfering with or finding away to earth through it.the banging could be backfiring. when it only revs at 28 is no4 firing as normal. what i forgot to to mention take the plug and coil out make sure its earthed use a bit of wire turn it ove see if its sparking if so its an injector or injector driver issue on my 80s cossie the drivers are in the ecu i wouldnt imagine yours is all that different try swopping the injectors around if possible to see if you can move the missfire to another cylinder if the missfire moves to another cylinder its the injector if no4 plug is firing and the miss doesnt move its a driver fault not unless the head gasket is leaking near no4 cumbustion chamber and spraying water over the plug i wouldnt of thought so though you would be loosing coolant and not pressurising because its going straight out the exhaust take the top off of the ecu see if its had a melt down in there it will fukin stink if its shit it self in there