Alfred, if you are having a problem with multiple injectors, then I would be looking at a different cause. What is more likely to happen, 4 injectors start acting up or a single problem with a fuel pump. The first check I would do is checking the fuel pressure. SHould be 40-50 psi with the engine not moving and the ignition key in the RUN position and 30-40 psi with the engine running. This check is really easy. All you need is a $20 gauge and then you screw it on to a tire valve step looking piece on the fuel rail (just a hint, you may see a few of these under the hood, but they are all different sizes, the gauge will only screw on to one of them). If you are getting good pressures (as described above), then you are looking most likely at a fuel injector issue. In that case, do a fuel system cleaning first. IT can potentially save you a lot of money.

On a side note, if it is the fuel injectors, when was the last time the fuel filter was replaced? If you don't know or it has been more than 15,000 miles (25,000 KM), it is time to do that to. The filters are cheap and if you have any mechanical aptitude, you can replace it. THe filter is located just in front of the right rear suspension components.

In your case, I would recommend a professional cleaning. You can try using a product called BG44 fuel injection cleaning. This is probably about the best stuff out there without getting into the professional fluids. Probably a good place to start before letting a shop rip into the engine.

Wish you lived near me. I would tell you to come on over. We could put all new injectors into the car for what the injectors cost. But, unfortunately, we are quite a ways apart.

Start with the BG44 product, see if you get any improvement. Next, check the fuel pressure levels, then go in for the professional cleaning, finally if things are still not corrected, into the shop for engine repair.