i am new to this site but need help asap. i have a 2001 cobra with 14000 miles that the dealer can't find the problem with. the symptoms are as follows: start car in am after sitting all night and it runs great for about 2 miles up the road then it is like you throw a switch and the hesitation begins.happens in all gears but easily noticed to anyone in fifth gear. from 50mph up when you accelerate hard it will bog and slowly pick up speed.it does this in all gears and fuel consumption is up 10-13mpg around town. the dealer can't find what is wrong and has had it for 2 1/2 weeks. he has tried the svt help line and now they are talking about flying in an engineer. it has never thrown a code or tested out of range. it feels as if the timing is being retarded and it won't go. this all happened one day while driving on the interstate at about 80 mph . i went to pass a car and it felt like i had lost 50hp. the only aftermarket part was a k&n filter i had put on 2 days prior. i didn't overoil the filter and the first dealer replaced the fuel pump and maf sensor but with no changes. car has been doing this for 1500 miles not getting any worse or any better. fuel additive was added and different premium fuels were used with no changes. please help as they have me in a loaner escort.