hello, I have just joined as I to have the same problem. I have changed fuel filter, then fuel pump to walbro, then I changed plugs,and the car keeps doing all wierd and horrible things. each time I changed something the car would run fine until I gave it and then would just run like sh*t. I upgraded from standard xr6, but starting to wish I had my other one back. after 2 years did not miss abeat. not happy.