ok...i was driving along last night for probably 20min when all of a sudden my neon dies when i stop at a stop light. it takes a few seconds to get it started again and then i get 5 wonderful codes...12, 14, 24, 25, and 51. After it is started you cant get over 4000 rpms. any ideas???¿¿¿¿¿

 

All of those except for the 51 are related to the 5v power supply - the MAP (14), TPS (24), and IAC (25). All 3 of those are used for the fuel trim calculations, which should account for the code 51 (fuel system lean) which probably means the PCM is adding way too much fuel than you really need, which would account for not being able to rev very high...

Trace the wires back from those sensors (MAP, TPS, IAC) and/or from the PCM (pin 43, violet w/white tracer wire), preferably with a multimeter, until you find the break.

Best of luck!

 

i will give it a try....Thank you!!!