Maybe one of you guys can help me with this....

When I accelerate hard in third I have some serious hesitation at around 3000rpm's. Once I've broken through the 3000 it goes away. Also this only happens in third(I have a 73 4-speed). If any of you guys might have a guess as to what is causing this to happen I'd love to hear what you may think it is. Thanks.

Please provide more info ie: What year is your Z for starters. Is it a 280zx 280z 240z etc... Fuel Injected??? Carbs? Electronic Ignition, Points Distributor.

From the limited info I can think of a few things.

1.) Flooding

2.) Fuel Pump but you say it goes away.

3.) Something electronic if fuel injected..

4.) Spark plugs? Leads?? Coil.

If it has an older distributor, the first thing that come to my mind is the advance plate is either cracked or the bearings are falling out and the advance plate is hanging up.

3K would be about where your vaccum advance should be all in, so perhaps it's either an advance problem inside the distributor or the vacuum advance itself is going bad.

Its a 1973 240Z it has the 72 carbs on it and I just replaced the plugs and wirers about two months ago. Also please note that it only happens when I'm in third gear. Hope that helps a little more.

When you say "third gear", is it because there is a load on the motor? Do us a favor, shift early, put a load on the motor, and tell us if you experience the same thing...

Thanks,

~Bri