Sticky idle issue

[Gnomesworth]

HI everyone i need help. Going to be along winded explination so sorry in advance. 

 

Recently bought a 2000 1.3 pickup with 66000 miles on it.  oil + filter changed, new battery fitted and new alternator put on 100 miles before i bought it. 

 

It has an issue of the idle sometimes sticking pretty highly when the engine is both cold & hot on start up and even after driving it around for a while and sometimes working as a cruise control keeping the car driving at low speed. 

 

Mostly the car will sit at a low idle fine but now and again will just stick on high but it will drop down again after i give it a few blips of the throttle. 

 

Taking the air box off the top of the carb i can see that its the electric choke thats physicaly keeping the butterfly open causing the high idle but as far as that i cant figure out why.

 

So far i have tried

 

spraying cleaner in the throttle body with the engine off and while running. 

 

Taking the sensor out from the back of the throttle body and cleaning it. 

 

Plugged in an obd2 unit that worked once reading codes but now fails to connect to the car properly saying there's a connection issue. 

 

Unplugging the connector to the choke solves the problem but then the car has a delay in throttle response and effects the drive-abilty so thats not a great solution. 

 

My latest idea is leaning towards the temperature guage on the dash. It stays completely down and will only rise to the first line if sat in traffic for about 5 minutes. So my thinking is that there is a sensor fault making the car think its cold and therefore the electric choke ramps the idle up. 

 

Any help or ideas welcome as im completely stumped and cant find any other cases of this online to help.