misfire on 911 3.0 sc

[Guest]

got a very slight misfire at 2600 revs changed the leads plugs filter anyone got any ideas before i get my hat nailed on at the rlling road cheers

 

[bones]

Two other inexpensive items you could change are the distributor cap and the rotor after that you you've gone a long way to solving the problem, a misfire at a specific rpm is often associated with fuelling issues I think a Bosch diagnostic test or similar is the next step. When did the car last have a tune up?

 

[Guest]

thanks for the reply the car has just recently had a service but i dont know when it last had a tune up wasnt very happy with the service any way i seem to think the4 same thing as you would you try any type of injector cleanser aand can you put forward anyone in the manchester area who can offer the tune that you have recommended thanks

 

[bones]

I couldn't quite unlock the typos in your latest post but if you mean should you try injector cleaner then that won't harm, I use redex but as your misfire is at very specific rpm then it needs investigating, it 's like a problem often associated with carbs called a flat spot, I can't recommend anyone in Manchester ask your local RO.

 

[bruceb]

If the misfire is at light throttle loads it is possible that the injectors are slightly blocked. They are easily removed and if taken to a Bosche agent will likely charge under £50 for cleaning all six. This happens to my SC every three years or so as it is not used regularly enough, the car runs much smoother after.

Another issue worth checking is the new plugs, I had some bad Bosche plugs a little while back that gave all sorts of strange misfires after servicing. It took a long time investigating fuel and ignition systems before changing back to the old plugs cured the problem, an expensive process to learn that not all spark plugs are defect free

Bruce
83sc