Rough Idling

[Jarrod]

Hello fellow calibra owners,
I hope someone here will be able to help with a problem with my 97 Calibra 8-valve automatic. I have had it for 11 years and before that my Grandmother had it from new, so I would like to keep it going as long as possible. Please note that I am not experienced in car maintenance.
The problem is intermittent, but when it presents the symptons are;
Engine starts, then stalls or runs "rough", my local garage described it as "hunting"
Pressing the accelerator has no effect, though sometimes releasing accelerator results in the revs increasing
Sometimes, eventually I can rev through it and the engine then runs normally
It happens any time but seems more often when need the engine is still warm
The engine warning light sometimes comes on but usually not
Even when running normally and warmed up, the idle revs are are about 700 rpm or below
Has anyone seen this before or know how to fix it?
Any advice will be greatly appreciated
Regards
Jarrod