So, my car has had this issue for quite a while now. I decided to finally fix it, but have no idea what is causing the issue. I am hoping someone can point me in the right direction.
When I first start my car in the morning to head to work, all is great. It has full power, gets up and goes like a typical Buick 3800 engine does. Once the engine gets hot, though, I notice a significant loss of power. It chugs, bucks, and hesitates going up hills, accelerating, etc. Anything over 2000 RPM will make the car do this AND in any gear (so I know it isn’t the tranny). If I stop the engine and then restart it, it acts as though it is going to stall (low RPMs, then recovers, then low RPMs again). After doing a little bit of research, I discovered that the O2 sensor is the likely culprit. So, I replaced it. Doing so has had no effect whatsoever on the issue. I really don’t want to dive straight into replacing the ECM, but that is really the only thing I can think of as the next step.
I am hoping some of you may have had a similar experience and could help point out the culprit.