too much or too little fuel. in relation to the air intake... i.e the mixture is wrong, and stops igniting... the reason for that might be a faulty injector... or faulty injector feed line... maybe an injector is not closing properly... until the revs change.. maybe its not opening properly until the revs change too much or too little fuel in relation to the air intake.. means the ecu will try and compensate to set the mix based on the oxy sensor input.. and if the injector input fluctuates the oxy sensor starts telling the ecu all kinds of false positives.. and so two things start to happen at once... if the mixture is lean .. the ecu richens it... if its rich it leans it... and all the time the faulty injector is allowing something different to happen,,, so either the ignition leans out and falters or gets rich and falters. the plugs might tell you that.. if you let it stop when it falters, and look carefully at them... since.. if the mix is rich it will foul the plug and it wont fire... if its leaning out.. the plugs will be very white and dry...
if it not a faulty injector... then either its an air leak or the ecu is going awol because the iacv isnt working properly.
because the fault is semi permanent, and only goes away under particular circumstances.. then its got be fuel and air mix error., or the ignition circuit
it could be the iacv not closing or opening properly... since the ecu might be telling it to open or close more.. but it doesnt.. its sticking.
if the mix is right and the ignition circuit is good.. the engine will run... if its not... it wont..
The worst scenario would be your getting conductive vapour in the cylinders ( coolant ) and that happens at the time of engine warm up... and goes away when you rev hard... the indicator of that would be loss of coolant, oxy error, and bad idling... spark plugs will fire to the nearest earth.. and that might no longer be the plug tip, if its wet.
i think you need to look at the plugs carefully.. when the fault occurs... ie let it falter and die, then take out the plugs and look at them. Also, bear in mind an electrical wiring fault, might only happen at a particular moment... based on temperature, proximity, and function... ie a bad connection only happens when the circuit is at a particular moment..
Last edited by Incony; 20-06-2017 at 14:23.