Sounds like too lean mixture. This will not be caused by injectors but more likely the air mass sensor and/or the oxygene sensor.
Get a diagnostic readout, that would tell and save you some money, although an air mass sensor is not cheap. If the problem is air mass sensor, you may be lucky since it may simply be cleaned (read some threads about it).
Don't keep running in that condition, or the catalytic converters may break down and spread out in the exhaust system.... and a new set of exhaust system, catalytic converters and air mass sensor really is an costly affair (I can tell, because I tried exactly that with exactly your symptoms).
So go carefully.