ok, 1997 Bonneville SSE

I'll start it up, it will idle rough for 5 to 30 seconds, rev up to around 2500rpm come back to idle and be fine. It has done this since I bought it 6 months ago. I knew about it when I bought it and it never really bothered me until now. What could cause this? It has new plugs and wires as of about 3000 miles ago. (it has 154,000 on it) I really don't wanna go to the dealership and be charged $100 for them to tell me whats wrong.

Ideas?

I wanna change my fuel filter, O2 Sensors, and clean my MAF but my dad just wants to go to the dealer because I don't know whats wrong with it.

Put some injector cleaner in the tank, check for vacuum leaks, check the PCV valve, check the EGR valve, check for a clogged air filter.

That sounds wierd. I haven't heard of something like this before. It will be nice to know whats causing it.

injector cleaner was done recently, air filter is damn near new, we checked for vacuum leaks the first week of owning the car, and how do i check the other 2?

Remove the PCV valve and shake it. If it rattles it'* good. Remove the EGR valve and inspect it. Did you check for vacuum leaks on the EGR tube?

im not sure what we did. we checked close to 6 months ago. where are the egr and pcv valves located?

The only other thing could be the throttle position sensor.

i unplugged that earlier today when it was idling ok and i didnt notice a change. should i unplug it and start it up?

No, leave the TPS plugged in. Try unplugging the MAF and start it. It will run rough for a bit and then smooth out. If the problem goes away then your MAF is bad. If there'* no change, the MAF is good.

Wait, you unplugged it while it was idling and no change in idle? It'* not showing an engine light is it?