2001 silverado dies when idling, but runs on high RPM

the issue first started about 5 days ago, i stopped to get food at a restaurant, the truck sat idle in the parking lot for 20 minutes, and when i wne to leave it started for about 5 seconds then died, it then started again, but does after putting it in gear and moving in reverse for 10 ft, then started again and died trying to move forward, if i give it gas at the right moment and get the RPM above 1000 it will run, whether at idle or in gear. quickly got it in gear and was able to drive it the 5 miles to my house. the next few days everything was fine. the day before it completely died it again drove 8 miles to a location fine, sat for 5 hours, then when trying to leave had the same issue, but was able to put it in gear and accelerate in time and it was fine on the way home, even stopping at stoplights/idling 4 or 5 times. Because it happened a 2nd time but the check engine light was not on i did some research they said that it could be a vacuum issue, and was trying to monitor things to see if i could figure things out. vaccum was 18-19in/hg on idle, as low as 2.5 on acceleration, and averaged 8-9 traveling around 30-0mph. Obviously i can't see transparent air moving to find a leak. I meant that i inspected all the hoses and connections, I do not see or feel any cracks or breaks, or hear any hissing. it dies immediately so any vacuum leak i assume would be a big one, i have gotten it to keep and idle once after timing the gas pedal raising it to 300 RPM and slowly lowering it down. it then idled around 600 rpm and i again moved hoses, felt and listened with nothing being detected. 2 sources suggested running propane torch (unlit of course) around the vacuum hoses to see if the engine RPM or O2 sensor voltage changed, i did that and did not see or hear any changes. also pinched off the brake booster vacuum with no change as well. I tried disconnecting the MAF as suggested by someone else supposedly it should run but rough using a default value, but disconnecting the MAF made no change, if anything it died faster. i also tried taking the cover off the air filter so air flowed into the MAF, but was not restricted by anything, also no change. The fuel pump draws 4.9amps when priming,and doesn't sound abnormal/problematic. The engine doesn't start long enough to see what the amps are when running. I was going to change the fuel filter as a precaution but the flare nuts are rusted to the lines, so i opted not to mess with those and possibly break the fuel line and have yet another issue to deal with. My thoughts at this point or clean and maybe replace the IAC, or get a fuel pressure kit and check pressure/flow rate. i just hate throwing parts at things until its fixed :/ any other insights are appreciated. Thanks Matt