I have a 99 f-150 4.6 2wd. My mil is lit and the code is egr insufficient flow. My question is why are 5 of my readiness monitors reading incomplete? The battery has not been disconnected in 3 months, I have driven 4000+ miles since then, of all types of driving. Would the egr code cause this?

the monitors reading inc. are:
catalyst
evap
oxygen sensor mon
oxygen sensor htr
egr systems mon

Any info or suggestions would be appreciated!

 

A fuse may be open that feeds the computer memory.
This would reboot the computer every time you start the motor and result in all monitors not complete.
The 401 code is a specific trouble.
Good luck.

 

So i reset the code and checked the fuses, all fuses were good. I went for a drive to see if the code would pop back on like it normally does immediately after clearing it. It did not. I drove about 40 miles and the o2 monitors switched to ok. the only monitors still on are catalyst, evap, and egr. I wonder If the altitude has made the difference. I lived in wisconsin and the code would keep coming back. Now I live in nevada at a much higher altitude and the code wont pop on. I guess I keep driving to see if the rest of the monitors reset, or the code pops on. I only need one more to switch on to pass smog!

 

The Evap monitor will be on for quite some time because it's diagnostics are quite involved.
If there is a code involving the EGR system, it is a trouble to be repaired so it's monitor won't clear until fixed.
Otherwise it sounds like everything is normal.
Good luck.