daf lf?

ive got a daf lf that if you drive quarter of a mile the engine warning lamp comes on and the truck dies but then picks up again, this used to clear itself but now it wont it keeps dieing and picking up but the further you drive the worse it gets. weve changed all the fuel filters, the pre filters, fuel pipes, cleaned fuel tank, changed intercooler, changed air filter we are stumped can anyone assist me please