Hello, I've been searching around but have not really found someone follow up with what has fixed their issue. So here's what's going on with my 2005 Neon SXT. It currently has 133,000 miles.
Last week I was driving down the highway and all the sudden the car started bucking, engine light came on, and so I pulled over. Tried to speed up again and couldn't get past 40 mph because it would start bucking again if the rpms were too high. I got to work, did the key trick to get the code, and the only code shown was P0340.
I drove home and the problem did not occur again, car drove normally. I thought maybe just a random occurrence. The car drove fine for another 2 days. On the third day it happened again, bucking/misfiring while driving. Same error code, and the only error code. Car still starts and drives just fine. Since the car starts and drives just fine I think that rules out any timing belt issues. I did have the timing belt and waterpump replaced about 10k miles ago when I bought the car.

Searching online I have found:
1) Replace Camshaft position sensor
2) Replace Crackshaft position sensor
3) Replace Vehicle speed senor
4) Replace PCM

Does that sound right or is there something else to look at?

 

This afternoon I replaced the camshaft position sensor ($25). I noticed the PCV valve was covered in crud on the outside and it appeared it was dripping crud onto the camshaft position sensor connector. So I also replaced the PCV valve and cleaned off the camshaft position sensor connector.

I'll drive it to work this week and report back if the problem continues.