I am completely at my wits end hopefully someone will have a solution. My 99 Camry suddenly started hesitating when accelerating from stop and at highway speeds. Originally checked the spark plugs and switched them all out as I noticed that one was completely black however this had no effect. It was shooting a code of P0401 at which time I replaced the VSV, modulator and EGR valve. I know that the modulator was not working as it wasn't even moving the EGR when we replaced it. Once the modulator was replaced the EGR began to operate again and on test drive it appeared the problem went away until I drove approximately 10 miles and it started up again. Now the problem is still there however it is not as persitant as it was. Tried replacing the MAP sensor and that had no effect at all. The check engine light is currently not on and not blowing a code however this has been intermitant from the begining. I believe the vaccum lines are fine as I tested them and they have air flow without leaks. If anyone has any ideas I would greatly appreciate it. Thanks!:headbang: