Does a 1992 F150 Custom 4.9 L6 have an evap cannister purge valvle/solenoid and where is it located?

Whats FUEL pressure at the fuel rail? This is the old Ford "speed density" injection system in closed loop its reading Manifold absolute pressure, Throttle position % and 02 sensor to fuel correctly 14.7 It could have had a purge valve stripped off but that doesn't explain the engine loping. whats intake manifold vacuum reading at idle? ROUGH running signals misfire to me! Fuel or lack of / ignition or lack of ....intermittently any of this temp related or wet / dry detectable? I want to locate this issue! Quit counting blinking lights forget the codes for now) even if your taped into that old Ford test port with an adapter and reader. Start by trying to isolate circuits / subsystems ...Example pull the EGR vacuum hose any change 0 Ok check back Friday ..Regards

Okay. I've checked all the voltage to and from sensors. They all seem to be within range. I will check the manifold vacuum reading. But this may also be helpful: on a Ford blog sight I found the recommendation of restricting the EGR orifice to 7/32". I did this and the engine ran smoothly but seemed to have less pick-up/power. My goal is to have the engine run as it was designed. I've read where others have had the same problem, as in the blog mentioned above. It seems like a common issue. One would think that someone would know the fix for this.

I've also replaced the fuel pressure regulator, which was the only part I was able to definitively determine was bad. After removing and turning upside down, gas came our of the vacuum nipple.

Did you ever figure out if there was supposed to be a purge selinoid plugged into that female connector along the fuel lines?

I research this issue whenever I find the time. I have restricted the EGR flow, which allows the engine to run smoothly but does not answer why one has to use this fix. One thing I read in my research is that the catalytic converter may be partially clogged and causing too much back pressure at the exhaust manifold and, therefore, the exhaust tube feeding the EGR, forcing the EGR to open. This would also explain the CE light and subsequent tests to indicate an EGR position issue that does not occur when the exhaust flow is restricted by the "fix."