My 92 5.0 with E4OD trans 93K on engine has a slight miss while at contast speed , it not contast more like a bump and then another . Pulled codes got a 311 Thermafactor system . Pulled the vaccuam line off the EGR and the miss is gone CEL comes on as expected , anybody have any experince with a problem like this ?

 

There was a common problem with some of the early EFI 4.9L engines with the exact same symptoms. In those cases, the solution was to install an EGR restrictor plate between the valve and the manifold. I've never heard of this being an issue with the 5.0L though. If disconnecting the vacuum to the EGR fixed the drivability concern, try removing it and cleaning it up. While it's off, make sure the EGR passage in the manifold isn't clogged up with crap.