on my 85 t/a 305 tpi when i start the car cold (i.e. in the a.m.) it idles fine-right where it should- but if i drive it somewhere and start it when its still relatively warm (like at school maybe 6-7 hours later) or any sooner and the idle goes right to and stays at about 1500 rpm if i try to kick down the idle it will either stay the same or go up slightly. but if i wait until the next morning it is fine again. when i look under the hood i can see bubbles rising up through the tube on the inner side of the coolant bottle, anybody know what this could be? i was thinking maybe the thermostat could be bad but im not exactly sure, it was a small problem but is now more frequent and i hate putting the car into gear at that high of an rpm. thanks in advance for your help

if you open the "expansion plastic resovoir" and smell in it when the bubbles appear, does it smell regular coolant or do it smell exhaust gases ? Cause bubbles in that tank could be a leak in the heads.. if it dosent smell exhaust you prolly fine.

How are you injectors ? have you checked the values (VOM meter needed) and what about your fuel pressure when the problem accours. ? whats your timing ? have it checked at idle when the problem occours to, get back here with some info about what I asked for and ill try helping out :-)