Anthony DiBernardo

My 80 911 SC Euro is not revving quite as smoothly as it should through the rev range, partuculary right around 3000-3300 rpm, (where I often hold for speed limit purposes) if have been feeling a subtle misfire.

My first thought is to replace the ignition wires but I don't want to just throw money at the problem and feel this is something I can fix myself.

I do not recall ever replacing or servicing the fuel injectors and the ignition wires are less than 10 years old. The distributor is 6-7 years old. Car is driven regularly, but annual mileage is probably < 4000.

Any suggestions would be appreciated.

TerryShugart

I'd suggest a look at the plugs, On the injection you can check the spray pattern of the injectors on a CIS equipped car. On mine I tried cleaning (shop service) and in the end replaced them.
Terry
75 911S

Steve Weiner-Rennsport Systems

How many miles since a major tuneup?

Anthony DiBernardo

Thank you for the responses.

I think its been over 5 years since I changed the spark plugs, fuel filter, air filter, etc. It has been about 2 years since my local 911 guru had the car running perfectly with a tune-up.

Mileage unknown between servicing but I would estimate its been around 15,000 miles since the plugs were changed.

I may work on changing them this weekend.

Anthony DiBernardo

UPDATE:

I changed the plugs. All looked good except for the #3, which was slightly fouled (dry). I also smelled fuel when the #3 came out.

The problem persists. Whats next?

TerryShugart

I'd suggest that you make sure #3 is firing as it should. I'd also check the injector. You can pull it out attached to the fuel line and put it in a can or something. Remember that this thing sprays at like 75psi. Turn on the ignition and lift the air plate. I'd want to see it spray but also stop when the plate drops and not dribble. If in doubt you can check another for reference.
Terry
75 011S