Bartamos, thanks for your interest. Answers below.
1. The motor "won't run at all" with hose plugged? CORRECT
2. The truck won't crawl in first gear whether hose is plugged or not? WON'T CRAWL WITH HOSE NOT PLUGGED; DIES WITH HOSE PLUGGED
3. It won't crawl like you think it should after warm up? CORRECT
4. When was the last time it would crawl like you think it should? DON'T REMEMBER / WASN'T AWARE
5. You have never said how it runs down the highway after warm up. Stopping at stop signs and acceleration and so on. I DON'T DRIVE IT MUCH; IT'S NOT STREET LEGAL AT THE MOMENT. THE OTHER DAY I PULLED SOME SHRUBS FROM MY YARD. IT WAS WARMED UP VERY NICELY. I DROVE IT AROUND THE CUL DE SAC AT 10 MPH AND IT DROVE FINE. PULLING IT INTO THE BARN AFTERWARD, IT WOULDN'T CRAWL ON LEVEL CONCRETE. I HAD TO GIVE IT GAS AND WAS MOVING FASTER THAN I WOULD LIKE TO WHILE TRYING TO PARK. REALLY HAD TO WORK THE CLUTCH TO LIMIT MY SPEED
As you suggested, I removed the air filter, ensured the choke was wide open, started it, let it warm for a minute so it would idle, then placed my finger over the vacuum port at the intake manifold. It died immediately. (I typically don't remove the air filter to verify the choke is open, because I know how the cable linkage is oriented when the choke is open or closed. Long story as to why I don't use the choke cable at the moment).
It's raining here so I can't do much testing with the engine running, because I don't want my truck to get wet (nor breathe carbon monoxide). Do you think I need to adjust the idle, or do I have a vacuum leak?
