Vibration

[f1worldchamp]

Hi guys
I have this strange vibration in the 75. I'll do my best to explain and I hope someone can help.
It's a 2.5 V6, '87 model. Revving the engine stationary, every thing is fine. However, take off and the car vibrates badly between about 2200 and 2800rpm. Above or below that and it runs smoothly. I thought is may have been an injector problem so I put some injector clean in the last tankful and it seems to have helped a little, but not eliminated it.
It very consistent with the specific rpm range, and it only happens with the engine under load, in any gear.
Any ideas?
Thanks
G

[dehne]

does the gearshift shake when this happens

[f1worldchamp]

does the gearshift shake when this happens

Nope. Just took it for a spin to make sure. It's worst through the steering wheel (the power steer has been disconnected).

[dehne]

it might be a long shot but have you hit any gutters with ur wheels latly maybe you have knocked a weight of there for you get a shutter effect through ur steering wheel

[Sheldon McIntosh]

Could be a spark plug maybe?  Probably worth checking the easy stuff first.  It's pretty easy to oil up the plugs in these.  Had it idling for a long time recently?

[f1worldchamp]

It's actually been the opposite. I've barely driven it in the last few weeks cause of the storms, and construction going on at my place. That's why I'm confused that it came on so suddenly.