My truck has suddenly developed a problem where it won't idle. It runs as long as I give it gas but the second I let up on the accelerator, it dies. A quick look under the hood shows that the heat riser spring has fallen off. The valve was in the "off" or warmed-up position. Could this possibly cause the problem I'm having? Float bowl in the carb is full, gas seems to be getting where it's supposed to go, all fuel line connections are tight. I know this could be caused by a number of things but I'd just like to know if the missing heat riser spring could be one of them. FWIW, the stalling happened after the truck had been sitting for a while, so I was running a cold engine, with the riser valve in the warmed-up position.
