Mechanics

HELP. P0300 AND P0302

2004 Dodge Neon

Computer problem
2004 Dodge Neon 4 cyl Front Wheel Drive Automatic 101900 miles

Well, as a former mechanic this is embarrassing, but I still don't know what the problem is and I need help.

It all started when I noticed that the engine ran just a little rough at idle. Soon after that, the check engine light came on and the code was P0302 " misfire at cylinder #2" and before I could do anything the light went away on it's on so I ignored it.

Later, the light came on again I checked it and it was the same code. I replaced the plugs and the cables, erased the code and it all seemed fine. Later the light started flashing so I scanned the car again the this time it was the old code plus P0300 " multiple random misfires".

I replaced the coil and cleared the code. It all seemed fine until at a stop light the " mil" came on flashing once again. At this point I am lost without a freaking service manual in order to know what to look for. I can think of several things that can be causing it but I need info in how to troubleshoot my car the right way. I have limited funds and it will be impossible for me just to replace parts and hope that was the problem.

When I drive, the light is on but not flashing, then when I get to any stop the light starts flashing. I am sure that the engine senses the unburned gas and it does not want me to ruin the catalytic converter. So it makes the light flash.

Please help me I really depend on that car. I am thinking that it could be the crankshaft position sensor but then again why only when the car is idle? Also why it is telling the that is cylinder #2.

Ideas anybody? Thanks for your help!
Avatar
Diego1616
November 29, 2009.



Hi diego1616 and TY for the donation

P0302 indicates a specific cylinder misfire-should prompt you to check the sparkplug, compression and injector for that cyl.

P0300 Random Misfire normally points to vacuum leaks and bad fuel

Misfires can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.

Rasmataz
Nov 30, 2009.
I have had the same issue for the last 30K. I have done the following. 2 sets of plugs, wires, replaced #2 injector, cleaned fuel system and checked fuel rail, installed new MSD coil pack, checked for vacuum leaks. Cat conv is not plugged, use good fuel and change the oil regulary. This car use to get 40MPG on the highway but now down to 30MPG. Currently has 110,000K on it.

I plan to do a comperssion test as well as take a look at the throttle body. If you have any luck, let me know.

I too work on cars regulary but this one has made me insane. I have read many posts on this issue and it just seems that no one knows what is going on especially the dealers. I was so frustrated I wrote chrysler and they never responded. I an getting to the point where I may just rebuild the engine.

Tiny
Cudafox
Feb 16, 2010.