Just as an update to this. Had the valve replaced at the dealer yesterday, along with getting the tires rotated, brakes examined and asked to have them check for an occasional shudder I would notice after the Compass was driven a while and when I would start out from a dead stop.
With the valve replaced, so far I've noticed a much smoother response when applying the gas then previously. In the 45 miles driven since then (from the dealers to home and then to work this morning) the average mileage has also bumped up by roughly .5mpg so far. The next time I fill the tank, I'm going to reset the EVIC setting and see what I start averaging. I was in the 21.8 - 22.5 range for a few months now. It will be interesting to see if this valve replacement takes care of that general drop in mileage that I described in another thread
Gramps, I know you were reporting both a slight drop in your mileage and the intermittent engine light a while back on your Compass too. My light had been off for about 3 weeks before heading into the dealers yesterday, but there was still a noticeable difference in the feel of the engine afterwards. I'll let you know how the next few tanks of gas seem to average out my mileage at.
The shuddering sound I referenced concerned me because I thought I might have been experiencing problems at the lowest gear ratio of the transmission, since that was the only time I noticed it, would have been starting from a complete stop, or when rolling very slowly without applying the gas. The dealer ended up replacing one bushing sway eliminator and verified the noise from the rear as well and loosened, lubed and then re torqued all rear lateral arms and links. Now it handles better then it did when I picked it up back in March. Feels very tight and responsive now.
Overall, not a bad $20.09 spent.