I've been having more problems with the idle and throttle with my 91 351w. It was reving between gears slightly before it came back down. Plugged it in and got map sensor and low egr feedback pressure. Then it stopped for about a week and ran fine. Today it started getting groggy and idling weird. Plugged it in and got the same two codes. The map sensor has been replaced three times and the last time with a ford dealership sensor. The egr has also been replaced once. I'm at a loss. Any thoughts?