I have a 78 F150 with a 4.9 that I TBId a couple years ago. It has performed fine till recently. Here lately it does not want to start. It will fire then instantly die. I can hold gas to the floor and get it started and it runs just as it always had....just wont start easily anymore.I think it is due to being too rich. I ran a log on WINALDL but cannot see anything that stands out. Coolant sensor reads correct. IAC is doing what it should. I watched the injectors while it runs, nice even cones. Am at a loss. Anyone have any ideas where else to look? there is no SES light. There are no codes I get. I do get some flags though:
IDLE COOL flag
DRP OCCURRED flag
ASYNCHRONOUS FUEL flag. Can anyone explain this one?
Thank you.

 

Connect a scan tool, check the data stream. TPS OK?

Verify fuel pressure.

How old are the plugs, plug wires, cap 'n' rotor, initial timing, etc.

 

It was the chip. I ran a log and adjusted the fuel a little bit and the chip would not verify against the buffer. Tried another chip with same bin loaded and it cured all.........VICTORY....lol.