My sisters car has been running a little rough, having trouble starting, and the Check Engine light has been going on and off on her for awhile now. Last time she was home my dad and I cleaned out her intake, air filter, etc. and it didn't really change anything, so we are thinking it is the 02 sensors, especially since my 3.4 acted the same when it needed new sensors. They are for some reason difficult to get out on the 3.8 or something, we had trouble even locating them.

Anybody have any tips on changing these out, and where is the best place to get new ones from? The car is a 1999 firebird with around 65k miles on it, maybe closer to 70k now.

If its not the 02 sensors, any ideas on what else could be throwing the light on and off?

thanks,

steve