mr farrar

hello everyone i'm not sure if i'm on the right page for asking questions but here goes,today the engine management light came on on my beloved jaguar and message restricted performance and sure enough when i put my foot down it stuttered badly and would do no more than 50 mph unless i accelerated steadily then it came up to 70mph,i have an obd reader and selected the erase option which cleared the engine light and message and also the performance was back to normal but of course i need to know what the underlying problem is,the reader first came up with p1111 then after i erased it the code was fault p1000 and 01 does anyone know the cause please?as i said the car is running fine now but for how long i don't know,i have owned the car for a year and have not spent a penny on it yet and it's s type 2004 auto with only 60k on the clock.many thanks in advance