[Blue)(Fusion]

I have a "light load" misfire ranging from about 20-50MPH. It happens in 3rd and OD gears when the RPMs and load are low. It is not torque converter shudder. I checked and rechecked. It does not present itself when idle or at heavy loads. When I get on the gas hard, the engine makes plenty of power and doesn't miss a beat. But when maintaining speed on a flat road, this is extremely annoying.

I changed the spark plugs in March which did not help any. I cleaned the COP boots and springs and applied generous amounts of dielectric grease which did not change anything. I checked for vacuum leaks, it's at 20" Hg when idle and steady as a rock.

When I disconnect the EGR vacuum solenoid it DOES go away. However, this leaves the engine running lean, EGTs hot, and stores a code for the EGR solenoid circuit which illuminates the CEL.

I removed the DPFE multiple times and tapped the moisture out of it. The hoses are connected correctly and the electrical connection on firmly.

When I apply vacuum to the EGR valve, it opens, I can hear exhaust gas flowing through it, and the engine nearly dies and then re-trims itself to a near-normal idle.

It has been around for over a year and I want to get rid of it once and for all. It seems to be getting worse in the warmer weather.

This is on a MY2000 4.6L in a Grand Marquis, by the way.