Stutter or misfire

[tonyl999]

My Mk3 GT6 has recently developed a bit of a stutter. If I am accelerating fairly gently and then ease of the throttle everything is fine. If I accelerate a bit harder and then ease of at about 3000 rpm I get what I can only describe as a 'stutter'. It almost feels like a backfire but without the bang. If I accelerate hard and then ease of the 'stutter' is even worse and can be quite violent and jolt the whole car. Has anyone any suggestions as to what may be causing this.

[Pete Lewis]

have you fitted a new set of spark plugs sound a bit like some are failing under load

 

and dont have any with an R in the suffix.

 

stick to plain BP5ES or BP6ES  etc.

 

Pete

[tonyl999]

Hi Pete. No new plugs and it's not when the engine is under load. It's when you actually lift off the throttle.

[dougbgt6]

It sounds like advance and retard isn't working properly which could be a vacuum leak. Manifold gasket? Carbs? Vacuum pipes? Distributor?

[Pete Lewis]

Check the diaphragm in the smiths emmision valve

and worth looking for small perforations in the carb ones too,

 

pete

[JohnD]

Do you still have points ignition?

Consider using an optical, contact breaker-less ignition system.

Lumenition have absorbed several previously independent  brands

See: http://www.rimmerbros.co.uk/Item--i-GRID006400

 

John