engine surge on 2003 Pontiac Aztek

the engine surges about 200-300 rpm while driving. I haven't noticed it as much during idle.

1 answer 2 comments
You may have an engine misfire causing your surge. Is your service engine soon light on? If so there should be a fault code stored which can be read with a scan tool. Any stored codes may help lead to the cause of the problem you are having.
I failed to mention that the light is not on. I am eager to fix it and any suggestions are very welcome. Thanks for any help.
It seems to happen while driving at a steady speed and more when the car is warmed up. It does not seem to affect it when accellerating up a hill (downshifts to maintain the speed) I had the injectors cleaned, but it made no difference.

I don't notice it while idling. I hope this additional information helps.
If you can give a little more information about your problem I will try and help if I can. Tell me if you feel the sure in the city or on the highway. Also, traveling a steady speeds or on acceleration. Any informaton you can give me about when the problem occures and what you feel may be of help.