Pontiac Repair: Service engine light on, pontiac transport, auto parts stores

Question
I have a 1995 Pontiac Transport 3.8 ltr engine. The service engine light is on. Took it to a mechanic and he stated that the coil paks needed to be replaced. He sayed the the engine code is tell him the the ignition switch is not toggling off. I replaced the coil paks. I diconnected the battery when I replaced them. After I reconnected the battery I started the car and the light was off. However once I turned off the engine and restarted it, the light came back on. I also notice that when the light is on the car bucks a little around 40 mph. Do you have any ideas?

Thanks

Answer
Hi Richard:

well the light being on is actaully a good thing rather then an intermittant lamp. the light one means it's a hard fault. I would stop by one of the big box auto parts stores and have them scan the van for codes and see what is stored in there and then you can go from there. If the Van has a lot of miles on it say well over 100,000 miles I have an Idea what it "could" be. on higher milage 3800 engines they start to set cam position codes due to the magnet on the cam gear breaking off then the cam sensor will not work due to the magnet missing that is the trigger for the sensor. If that is the code it coul explain the hesitation and it more then liley is getting worse gas milage as well. But again untill you know the code(S) I can't tell you where to start looking.