Driving home last night, while towing a small 5x10 tralier with 120 lbs., I had the engine light come on. Drove the rest of the way home with no problems. Got in it today and the check engine light was on. The truck was reving higher RPM's than needed. At first I thought the transmission was going. Took it to get the code p0121 read. The tech said it was either the Throttle body positioning sensor or the wires leading to it. So I replaced the sensor with a Mopar one. Tried it again with same results. I really don't know where to go from here except take it to the shop. Any ideas?

 

On an 02 with likely a 5.2/5.9 i have no idea

Maybe you can ask in the 2nd Gen section and see if they can help being they also have those engines

 

Your best bet is to take the trhottle body off and clean it real good, take out the iac and clean it as well. Use a good quality carb cleaner and start there. i believe there is a DIY for throttle body cleaning in the 2nd gen section.

 

I took the throttle body off and cleaned it. Also put Techron and 93 octane in the tank. Code is gone and is running better. I believe I must have put in bad fuel. Anyway, thanks for the advice. Dodge Forum helped me again!

 

Yep, any throttle body code it's a good idea to clean the throttle body. It may not always solve the problem, but it's NEVER a bad thing to clean the TB. I do mine every 15k miles and it ALWAYS is gunked up pretty good on the backside...