Jacob-911

Thankfully not literally - I have come from a 997, so know that could be a reality!

When accelerating, at 6k revs the car loses power - harder than if it hit the limiter and won't rev beyond 6k.

When stationary it will rev freely and there are no other issues that I'm aware of with the engine - other than this issue it drives great.

I'm thinking this is ignition related, so plugs, leads, dizzy caps and rotor arms. Is there anything else that I should try or has somebody else had a similar experience?

Thanks in advance

vincer77

Yrs, ignition is good place to start. Air filter also. Then of course, fuel.

You could also look at operation of vario-ram. With that operating, she should scream like a banshee through red line. There is a vacuum
rubber double tee behind heater that wears out and collapses defeating the actuation. But it wouldn't not rev, so ignition more likely.

jskylarwilson

Any codes being thrown? You could have something as simple as a sensor issue, or it could be vacuum, fuel, or a number of other things.

pp000830

The varioram can be tested by standing behind the car with the ignition off shortly after running the car and having an assistant turn the ignition on while you watch the engine. You should see two actuators on top of the varioram manifold and one underneath it cycle and the fourth one on the ductwork to the lower left of the engine compartment cycle as well. If all four actuate, none are leaking, get in the car and press the air recirculate button on and off a few times on the climate control unit. You should hear a vacuum actuated door open and close. If you do not hear something the actuator's hose may have come loose. IF all the five actuators work then you do not have a leak and the varioroam is working.

Also, I would not assume your tachometer is very accurate. The rpm can be read accurately through the OBDC port using Durametric or other full feature reader software.

I would also do a quick check of the distributor by running the car with the directly driven distributor disconnected and the once again with it connected and the belt driven distributor disconnected.

Andy

I am not a professional mechanic but my feeling is if your ignition was so bad that it was limiting rpm you would see all sorts of codes. My bet is it is a vacuum problem or a neglected fuel filter if the one in your car looks to be the original one.

Jacob-911

No codes have been thrown up and It's non varioram.

I hadn't considered the fuel filter, so shall also try add that to my list!

it also doesn't do it every time which I guess makes it a bit more tricky to diagnose.

nine9six

It sounds fuel related to me and a new fuel filter is probably a very good start. Try that and test... the issue only occurs when the engine is under load, at 6k rpm, right?

BTW, to your knowledge/records, has the fuel filter been changed before/when?

Jacob-911

Correct - only under load.

It's a new car to me and whilst the service book is fully stamped up, I only have receipts going back 3 years. The fuel filter hasn't been changed in this time. Going to give that a go and see if that works.

Churchill

First, don't rev your car to 6K with no load. Not particularly good for the engine. Your problem sounds ignition related. If the fuel filter was clogged your symptom would appear consistently -- fuel filters don't un-clog themselves. I would visually inspect caps/rotors/wires, then test coils.

Jacob-911

Thanks for the tip

nine9six

No, Chirchill is right...fuel filters do not unclog themselves, but they do get progressively worse.