Today I reconnected my EGR valve wires, and replaced the EGR valve. A previous owner probably had a bad EGR valve, and instead of unplugging the harness or actually fixing it, they cut the wires all the way down to the loom. Needless to say, I was getting about 23 mpg highway and about 19 city - with a GS.
When I replaced the EGR valve, I noticed some what I assume to be built up exhaust/gas/oil mixture. Reminds me of the oil that accumulates in the PCV. Should I have sprayed that out with intake cleaner or something?