More advice thanks!
The IAC valve disconnect didn't do anything, but I tried it. Might mean it's beat ! In other words it might be dead and that's why the truck starts hard. It screws in, has 4 leads. I dont know if it's solenoid or stepper motor type. I could back it off and see if it increases the idle. I guess it just bleeds air past the butterflys.
I can't diagnose with any sophistocation at all. Not sure if the TPS has any adjustment, I know some of them have rotational adjustment.
One thing I've learned is never tell an auto repair shop you just want to pay for diagnosis. It threatens and insults them at the same time.
The sensor with the red and black wires, right next to the thermostat housing, is cheap to replace. I could pull it but will have to drain antifreeze below its level. Then I could heat it or cool it to see if it is a thermistor-- change resistance with temp. I was looking around Rockauto to see what they have. ( Thinking about my swap parts until the problem goes away method that has never worked before...)
There's also an EGR time delay switch. It might function to prevent EGR from working until warmup. Along those lines, I put my finger on the EGR diaphragm and opened it which roughened the idle considerably. I'll pull the EGR tomorrow and clean it. Maybe that's it. That was replaced at one time- mad expensive for a simple device.
Old distrib is in it, plenty wear on it. I think I put a new gear on it though.
Engine has always had good oil pressure- but might have slack in the timing chain after 35k.
I got the 350 off EBAY! some clandestine machine shop in Philly. It was under a grand for a long block. I put it in at 165k when the old engine was clattering. The poor slob that delivered it couldn't get the gate lift to work. I fixed the gate lift, a straight box truck. It had dual diesel tanks. He hit a rock and knocked the drain plug right out of the right tank. Diesel was pouring out down our lane! I ran inside and cut a piece of closet rod and sanded it to a taper. Ran back out and banged it in like a bung! The guy drove away. I think this is a startup situation. It starts hard now even warm, but runs ok. Engine is clean, no oil leaks.