A couple of weeks ago, as I was driving in traffic in a large Michigan city, I stopped in traffic at a stop light, and all of a sudden, as the engine speed returned to idle, it didn't. It simply died. I didn't think too much about it, until the next traffic light. And the next. And next. Before I knew it, this almost became dangerous, as I was trying to keep it idling in neutral as I came to a stop and using my other foot on the brake. At least the engine started easily when it did die, and ran perfectly other than at idle. But there are other things that have me a little baffled too. For instance.
As I stated in my introduction post, I bought this car two years ago, in Coos Bay Oregon, from the original owner, who just happened to be a Toyota dealer mechanic, who kept up the maintenance at factory spec'd timing, and had kept a maintenance journal an inch thick.
A month before I bought it, he'd replaced all the vacuum hoses, water pump, radiator and all hoses, fuel filter and a half dozen other things not to mention giving it a full tune up. It ran perfect..and..still does, other than this new idle problem. But here's the deal. Even from the day I bought this, there was a problem with the accelerator kind of sticking when I even barely step on the gas. It's as if the spring on the throttle was weak, or broken and wouldn't return to idle immediately when I take my foot of the accelerator. I asked the owner about this and he said the only thing I could do was add another spring, which I never got around to doing. Also, it seems to run rich while normal driving, as I seem to smell gas. Not bad, but I detect it. But here's the relationship to the idle thing.As soon as this "idle" problem developed, it seems as if the throttle problem isn't happening as bad as before. Not only that, but I noticed a distinct difference in the sound of the "exhaust". Now it has a kind of "hollow" sound. Totally different than before this idle problem came up. But here is what I've done so far to find the problem.
I removed the air cleaner to do a visual inspection first. As my pro mechanic father always told me...LOOK LOOK..and then LOOK some more!
Over the years, I've learned that a lot of idle problems can be due to leaking or loose/disconnected vacuum hoses. But crap. I don't know if all the 82' 3tc engines sold in the US had all the smog equipment as Standard issue, but mine is loaded with it. So many vacuum hoses it's mind boggling 
Regardless, I checked to make sure none had come loose, or cracked, or whatever. Having found nothing, I plugged the two vacuum hoses that connect to the air cleaner, and stared the engine.Ok, at cold start, the engine started perfect, and remained idling during warm up. The choke was closed, and over a minute or so began to open. No smell of gas, no leaks. As the two large hoses from the air pump were now disconnected, I could feel the front hose sucking air, and the rear hose blowing air, even at idle. But slowly, as the engine warmed up and the choke approached full open, all of a sudden, I heard what sounded like a "valve" shut, and immediately, those air pump hoses stopped blowing and sucking air, and the engine started to die. I immediately opened the throttle to keep it from dieing, and as I did, that "valve" sound happened again and the air began blowing and sucking from the air pump hoses.. AND , the air pump sounded different than when that valve shut. Now, I don't know if this valve shut when the engine returns to idle is normal, but when it happens..that's when the engine wants to die. In fact, it seems as if the problem isn't even in the carb. But..that remains to be seen.
Ok, so, at that point, not knowing what any of these devices are that all these vacuum hoses are connected too...that's when I decided to search out some online help. VOILA! This forum. Cool. Not only that, but just before I posted this, I found a post by someone who linked to an entire service manual..which may make this post moot!!
I haven't even began looking through it, as I figured maybe someone might identify or diagnose the problem just from my description of the problem. At least now, I can look up the smog system and identify various parts. So, until someone might have a suggestion, I'll start looking up some info. Thanks for any help. This car is my daily transportation and I really need to fix it. Oh, and btw, any thoughts of switching over to a Weber are out of the question. I'm retired, and on a fixed SS income. Ok..I'll be back.
Ain't no way. Although it may not be one of these. Thing is though, I haven't had time to even deal with it this week, as another problem has forced me to fully focus on it. The electrical feed cables to my garage developed an open fault in one of the hot conductors. 
Geeezus..if it ain't one thing... it's 20. Not to mention I bought a 2001 Dodge van last month, that started knocking within 5 miles from the sellers house. It completely lost oil pressure..intermittently. I tried to make it home which was 30 miles. Didn't make it. As I really liked the van, I called the seller, who had already offered to give my $1200 back, and offered him $300. He took it. Now, I still have to dig into THAT can of worms too. However, this idle thing really needs to get fixed, as my wife needs to use the car too. And she is afraid of driving it in this condition. So.. onward.