I asked a similar question previously, and have also asked around quite a bit.
My car starts and runs fine for say, 20-30 km no worries, it also sounds like there is a slight miss on the engine, but nothing too serious. After say 30 km(never really checked exact distance) the engine feels like it does not really want to run. It barely idles(rev meter jumps between 0-500) and when I step on the accelerator, the revs picks up to maybe 1000-1500 and then drops again. Also while driving, when this happens, the car feels like its cutting out. I can drive slowly in 1st 2nd and 3rd. But when I try to accelerate, it feels like the engine wants to cut out, but as soon as I stop accelerating, it feels like it wants to go again. Weird.
A lot of people tell me that its my fuel pump and that its possibly overheating and because of the overheating, not supplying enough fuel to the engine.
If I leave the car for about an hour, it runs fine again.
I have replaced my spark pluggs as well as the 2 coils on the car recently.
I had a fuel line leak(at the injection system) that has been repaired now, but does tend to start leaking again every now and then(wish there was a way to permanently stop it from leaking)
I have now gone to buy a generic fuel pump, but have not fitted it as yet, as I have not got a clue on how to do it, if you guys maybe have a video/instructions on that?