Hi. I'm having a problem with my 4 barrel on my 72 Econoline 302 SBF, and can't quite figure what might be causing it. It has electric choke that seems on the whole to operate as expected. When I blip the gas pedal, the revs drop on the fast idle cam to normal. However, increasingly after driving it a bit the idle revs increase and if I pull the filter off I can see that the choke appears to have opened a bit again and it's running on fast idle again. Pressing it down with my finger causes the choke to switch off again the choke flap to lock in vertical again. I'm running the choke, so it's a little open when cold so the spring should be quite tight when it fully opens the choke flap. (I know there is a word for this, I just can't remember it.)
Any ideas where to start with this? Thanks, Jamie.