I got a big miss fire on cylinder 4

1 90psi
2 100psi
3 100 psi
4 100psi

Got a spark on all cylinders but even when I removed cylinder 4 lead the. Miss fire didn’t change

car was running fine untill this morning when I tried to get it up
on the ramps

 

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

 

No one is down on pressure but it’s no 4 crank end that’s missing

remove any other coil engine definitely gets worse but as said no 4 I can pull lead out and engine stays the same

ive put new plugs in

I will say I did have a omex Rev limiter installed even though it wasn’t switched on I couldn’t Rev past 2.8 k I them pulled the fuse on it completely disconnected from any feed car would Rev up fine but miss firing

and sensing out some massive bangs but that could be from cylinder 4 not firing correctly

 

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