I have an 86 Toyota PU with a 22r. It has california emissions. I have a couple of problems. I just rebuilt the engine and put it in the truck. It runs great except that it does not want to idle. It accelerates and runs fine on the road, however if I slow down suddenly or put the clutch in and let the engine idle down, I can hear it start the pop and backfire a little and then the engine will die. It starts right up again but it is a constant problem. If I give it a little gas when I am slowing down (clutch in), it will start to idle, but real rough (500 rpms). I cannot find a vaccuum leak, however on the passenger side of the truck is a switch that has two vaccum line ports on it. One of the ports has a line that runs to what my chiltons manual refers to as a "throttle positioner". There is another place for a line on the switch on the firewall, however, I don't remember taking a line off of it, and my vacuum diagrahm doesn't even show that particular switch. The switch I am talking about has an electrical pigtail that plugs into it and a small balck plastic "filter" on it. The switch is mounted to the base of the EBCV (chiltons term not mine), it is not the VSV (another chiltons term) Anyone have any idea what that is and where does the other line run to? I have looked all over and can not find any other place for a line. As per the diagram all my other lines are correct. Sorry aobut the abreviations, they came off of my vacuum diagram, however I could not find what they stood for.

Also, the timing on this thing is got my wondering. I set the timing at zero with a friend giving it a little gas to keep it at 700 rpms with the vaccum lines on the distributor disconnected and plugged. I then reconnected the lines and for the grins of it looked at the timing. It was exactly the same. I gave it a little gas and it advanced exactly like it did when the lines were disconnected. This seems strange to me. It seems that the vaccum advance was not working. How would I test the vacuum advance and how would that be corrected? I have the feeling that what ever it is, is the heart of my idle problem. As usual thanks in advance.