I own a stock sprinter with a 4ac. About a month ago the car developed what i describe as a random stutter during acceleration. I asked a mecanic about it and he said it could be crap in the carby, so I run some injector/carby cleaner through it with a tank of fuel. Apart from getting 50km extra per tank of fuel now, it didn't fix anything.
I also notice that the temp gauge needle barely moves up now even when im driving the car extra hard.(It normally sat at about half way).