I have a 1995 S-10 with a 2.2 engine. For over a year or so the engine has had a hesitation which will not go away. I have tried all the tune up stuff, plugs, wires and fuel injector cleaner. None of these things has helped with the hesitation. To elaborate on the problem, the engine is sluggish and hesitates up to around 4,000 rpm. At around 4,000 rpm the engine gets a power spike. Sometimes when pulling out into traffic the engine seems like it might stall out. The check engine light does not come on, so I do not know where to start. Could this be a bad coil pack or fuel injector? Any thoughts would be great.