1980 308 gtsi when i start engine stuck on fast idle warm up (HELP)

Hello i have a 1980 308 that i just bought not long ago the other day something really weird happen after taking a drive brought it back and started to idle high like when it does when you do the 5 min warm up.
Had some smoke coming out of reservoir hose. Since then was told to bleed the radiator system bought a new radiator cap and when i start the car immediately when you start it idles high. Any Help or idea what this could be ??? Any help would greatly be appreciated .
Looking forward to some answers hope its not anything major i just got this car in August only drove it like 4 times.
Thank You

 

Just in case it might be something non-technical, make sure that your floor mat isn't resting on the accelerator pedal. Yes, it has happened!

 

Ill check that to make sure Thanks for your help....

 

Check to insure the throttle is returning to idle position. Throttle cable could be getting stuck.

 

Or you could have a small vacuum leak that’s causing the engine to suck air to raise the idle.

 

this. It happened to me on new floor mats.

 

Did you check the oil and knock of the vacuum hose right next the dipstick?

 

Let me take a look at that i also notice that my gauges are all not working. This is really strange.

 

Did you have the O2 sensor hooked up? Some of these can be problematic. Disconnect and isolate the O2 sensor (just a simile connection) wrap the contacts - start the car and see if you get the same response