Well just thought I would stop on by here as I was looking for information online for my truck and I ran across this forum.
I own a 97 F150 4.2 L my county requires echeck and I have a check engine light on so I stopped by my local autozone store and they tell me its a insufficient egr flow and they look up what parts I might possably need to replace.
1 EGR valve
2 EGR sensor
3 EGR solenioid
I have replaced the egr soleniod and the egr sensor and also bought the egr valve, now I have yet to install the egr valve because I honestly dont think its bad I think the issue lays somewhere else. My reason for thinking this is I can feel very little to no vaccume going to the egr valve and what I do feel is kind of like a pulsating pull but I dont think its strong enough to open the EGR valve anyway. Does anyone have any clue as to what might possably be going on. Otherwise my truck runs great.

 

The port gets plugged with carbon. A simple cleaning may be your fix. Do a search, there are tons of posts about the EGR plugging up.

https://www.f150forum.com/f6/egr-pro...d-help-138727/