This article is from the Chrysler-Plymouth-Dodge FAQ, by Dr. David Zatz with numerous contributions by others.
There is a specific Neon FAQ.
This section of the FAQ may be eliminated soon.
* Many problems are caused by poor battery connections to the cables,
which can cause signals to the computer to be incorrect without
(or with) fault codes being registered. Check and clean the
battery terminals and cables first!
* Additional information on troubleshooting and repairs is on
the web site at http://www.allpar.com/
* Some of these issues are discussed in detail at http://www.valiant.org/
(a site dedicated to A-bodies like the Dodge Dart and Plymouth Valiant
and Plymouth Duster.)