Hi mate,
Dazz has mentioned this, what model, mileage etc.??
Glow plugs do not operate when the motor is hot, so $$$ wasted.
"
suggestion put to me today was an intermittent fault on the fuel pump..expensive ". Big Call
Who was this?
As a rule of thumb, Mechanical devices usually demonstrate failure by noise or poor performance then stop working! What you describe is more symptomatic of an electrical fault, it is like a switch being turned off...eg. sudden immediate stoppage. Or in your case, off and on again.
In Britain, going from
hot tepid weather conditions to freezing can occasionally cause electrical connectors to be unreliable. So while the engine idling physically move wires and see if there is a change.
I'm not sure if your "cough" is total power loss or partial. ??? If the latter, trace the vacuum lines, a solenoid may be causing your problem.