1.8 Golf engine troubles

[T5_X]

My friend's 94 CL has been going at about 40% for a little while now. The thing just won't go above 3500 RPM, so the car is so damn slow.
Anyway, we thought it was the fuel pump that was going, so he put a new one in yesterday. It had a little more kick, but not much more, so that didn't solve the problem. I think it's the injectors. He checked all the lines, so it's gotta be something closer to the engine. I thought maybe since his fuel pump was on its way out, a new one might give it a little more kick by blasting through the dirty/worn injectors better, explaining why the new pump did give it some more power. As well, since it isn't working at higher RPMs, i thought maybe it was cause the inector couldn't keep up at the higher RPMs. I asked him if he drives on empty lots and he said yes. I heard it's really bad for your injectors to drive on empty cause the stuff at the bottom of the tank (water, sludge etc) can get picked up and blasted through them, that would also explain why the problem arose fairly suddenly. Oh yah, and apparently the fuel injection system in this car uses just one injector, it works almost like a carbouretor by injecting into a butterfly valve then getting seperated into each cylinder, weird....

Anyway, questions are: What can he do for the cheapest amt.? Can he get them a good cleaning or rebuilt for cheap? If they're rusted out bad i suspect he'd need to replace them.. how much would it be for the part and could it be a do-it-yourself thing, or does a bunch of shit need to be torqued up right after, we don't have many tools plus it sounds like an odd set-up, I wouldn't really know what i was doing.
Oh yah, and is it bad for the new fuel pump? What other parts of the car is this gonna be bad for? I guess it would be running super lean right now.

[egmike]

I would try doing a Fuel Injection Cleaning first. It will prob cost like 100$ buks or so but cleans the injectors alot better than the stp fuel addititive type.
If you know a mechanic he might have the kit to do it. My old roomate had one and I did it on my driveway for like 15 $ which was the cost of the can of cleaner.

[T5_X]

i doubt it'd help much... I heard doing those flushes can do more harm than good, he'd want to get the thing taken out and looked at before he wastes 100 bucks on something that isn't for sure at all.

[rage2]

Is the check engine light on at all?

[ninspeed]

I would first chnage the fuel filter if you have not done that.. 2nd you can take the injector our and let it sit in a small bowl of gas over night.. then run some gass though it.. check that the throttle asseblely is not cloged with dirt inside and out.. (ive the engine a good cleaning with a can of degreaser and water) if that does not work.. pm me and ill come take a look at it (or you can bring it to my gargage)

[T5_X]

The check engine light is not on, and he changed the fuel filter recently.

Could a leak in the intake manifold possibly cause this?

BTW, I'm in Vancouver right now so we can't bring it in for you