help

i have a 2001 montana 3.4l and i took it in to have the spark plugs and wires changed. i also needed the ignition coil replaced. now when i drive it on the highway at 120km/h the rpm is between 3000 to 3500, before it was between 2500 to 3000 , could they have done something when they replaced the plugs or is it normal to have high rpm after having this done. thanks
tommy

i have a 2001 montana 3.4l and i took it in to have the spark plugs and wires changed. i also needed the ignition coil replaced. now when i drive it on the highway at 120km/h the rpm is between 3000 to 3500, before it was between 2500 to 3000 , could they have done something when they replaced the plugs or is it normal to have high rpm after having this done. thanks
tommy
It is not normal. It sounds like your TCC (Locking Torque Converter) is not engaging. It could be a vacuum leak, but I would take it back and tell them to fix it.

ok i took it in and they said it a transmission problem and got a code p1811 or p0748. is this easy to fix, they recomanded me to someone to do it. can i fix it my self.
tommy