On Nov 16, 5:43*pm, wrote:
> I recently bought a '90 honda accord. *It 'had' a bad vibration at
> idle, so replaced the dogbone in the front (torn rubber element) to no
> avail. *Then changed out the rear motor/xmission mount (what a bear)
> as it was the most probable cause and found it was indeed damaged. *Of
> course to do this I removed the intake manifold, so had to refill the
> coolant, replaced the gasket etc. *Now the engine revs up to 3500 and
> back down to around 800 and then goes through the cylce again. *I've
> triple checked vacuum runs to make sure I didn't swap something,
> checked for cracked vac hoses. *Can anyone suggest
> something...please...I've about run out of patience.

Sounds like a big vacuum leak. You can tru looking for internal leaks
by checking the egr and pcv systems. Also if everything is hooked up
properly again. if you need diagrams I can help.
lemme know
hondatech327