Why would my 2004 dodge neon not of second gear, it seems as though its stuck in second. I have changed the camshaft sensor, throttle position sensor, the computer, the alternator and the battery and I'm at a lose. And when I have changed those things it will seem back to normal and then 2 days later It will happen again.

SOURCE: Cam Shaft Sensor Problems

Had the same problem before on my 04 Neon SXT...camshaft sensor is on left side of engine block, take out the battery and to the left of it (face car) is the camshaft position sensor. To change it you'll have to move a few hoses but its plan to see there on the left side of the engine...pretty easy remove and replace. Fixed my problem of car not going above 2k RPM when i replaced the sensor.

SOURCE: Replacing A Throttle Position Sensor

the tps is attached to the throttle body. It operates the plate inside.

SOURCE: How to change the camshaft position sensor on a 2004 dodge neon s

try autozone.com to see if they have your car listed for diagrams pictures and step by step instructions if your car is not listed then try your local library they have all the car manuals and even copy them for you

SOURCE: I have a 2000 buick lesabre. The fix engine soon

It NEVER was the camshaft sensor! Unless, you've removed the engine lately, which I doubt.
RUN to Advance Auto Parts and buy a can of "SeaFoam" and add to your gas tank per instructions...drive at least 100 miles and the problem should go away...IF it doesn't you'll have to replace the O2 sensors in the exhaust system...Any good mechanic should be able to do this for much less $$ than the dealership DO NOT go to the dealer for repairs!
Good Luck

SOURCE: where is the camshaft sensor on a 2004 dodge neon

disconnect the negative battery cable. the cmp sensor is located on the left end of the cylinder head. move thebrake booster hose and electrical wires out of the way to access the cmp sensor. disconnect the sensor plug by pushing the locking tab back toward the firewall. remove the 4 bolts from sensor and lift out sensor. remove the trox bolt which holds the target magnet to camshaft. when installing target magnet be sure to line up holes to dowels on end of camshaft. torque torx bolt to 30 in-lbs. be sure to install new o-ring on sensor and torque bolts to 80 in-lbs. (hallclifford)