Pontiac Repair: over heating at times, temperture, speed fan

Question
1998 pontiac gram am 3800 engine v6 series 2
when driving the temperture is normal but in stop and go traffic the temperture raisers to almost the red zone and the engine runs rough. Then it comes dowm to normal range. this keeps happaning
all the time. I had the thermostat changed , replaced the radatior and replaced the anti freeze
with dex cool. Can you offer any thing i can look for. The fans only come on when the temp reaches about 220 degrees. Do these fans only have one speed ?

thank you  

Answer
The fans are supposed to come on at about 229 degrees. The temp should not keep rising after the fans come on. Your car could have a 2 speed fan depending on the options. If it does, the fans will increase speed at about245 degrees ( I think) or with the AC turned on.
Is the engine actually overheating or could it be that the gauge is reading too high?