ok i have a dodge neon 97 i put in recently like 2 days ago sum megan headers ....but i dont have a catback exhaust i did sum mods to make it fit and all...but my car just wont start...it started before just it slowed down abd completely shut off....my battery is fine everything is fine i checked every problem...i think its the o2 sensor but i have no clue...oh yea and it works like every 3 hours if i dont try to turn it on....but for like 5 min then it turns bak off....

 

Is your starter still connected, is your wiring still in good shape, check some of that out.

 

i checked everything....brand new starter the wiring is correct all the wiring is correct..i just have no clue why it keeps turnin off...

 

Really sounds like something got knocked loose during installation Installing a header for the neon is a bicth to do, check your fusable links that could be it, my car wouldnt start once because I blew one, once my car wouldn't even start because one of my terminals had a crack in it, had my battery checked to make sure it wasnt it and low and behold that terminal was nice and cracked messing up the connection reading your post again it sound like what happend to me but in traffic my car just locked up and lost power and shut down on me, luckly i had enough speed to get out the way if you can get a hold of a OBD II reader that would be great I dont think an O2 sensor would cause that, I have a high flow and have yet to put back the O2 sensor for the downstream, and the one in my Pacesetter header is bad, its a bosch one( I too fell victim to bosch but never again!), Hope something was helpful and good luck,

 

Neither O2 sensor will keep the car from starting or running. The one after the cat is just there to let the PCM know wether the cat is good or bad and turn on the CEL if it's bad. The one up by the engine is there to tell the PCM how the fuel/air ratio is, so that it can make the necessary adjustments. If this one goes bad or is disconnected it will simply run full rich and turn the CEL on. Running full rich can foul out the plugs, but it is normally not a problem except on a hot start after the engine's at operating temperature.

 

Fuel
Air
Spark

...my bet's on spark...

When you take the ignition key to "ON" (not "START"), does the Check Engine Light come on for a second and then go off? If it isn't, then the bulb is probably dead. Getting codes would be a big help. And if it just stops running all of a sudden, there's probably a code for something.

Best of luck!