92' 351 missing under acceleration but only when warm (EGR?)

92’ 351 runs great when cold but misses under acceleration when warmer up.
Mechanic read the codes and said EGR valve and/or sensor came up.
He seemed to have no idea if this would fix the missing when warm problem.

Could EGR valve or EGR sensor cause this warm only missing problem?
If not any other ideas what I could check?

Thanks!

Un plug the EGR and take it for a drive, no miss, bad EGR, Deal is tho, if the EGR is bad it usually shows up as a shutter or surge at cruising speeds.

bad egr can also cause an erratic idle. We have gone through 3 or 4 egr valves on our 88 351w, they seem to be a normal wear item. one about ever 60k. hook a vacuum pump to it and see if it holds, is another easy way to test.

one thing is that the egr is only activated when up to operating temp so it could be your problem. but i would test before dropping the money to get one, pretty expensive and I only recommend a stealer ship factory part, they last the longest.

The setting codes are 327 and 328 in continuous memory.

Key on engine off and key on engine running have no codes set.
Both codes indicate that the EGR system position sensor circuit is below the minimum voltage at times.