Well, changed a ton of things in 96 neon sohc. new coil pack, plugs, wires, cam and crankshaft sen., new fuel pump, and just put in new emc. the old one would not read any codes ready to test emission no matter what. but even with the old one had the 0300 multiple misfire code, had the new emc flashed and programed at dealership ready to test after drive cycle. less than 20 miles misfire code. Any help on this one. how can I test if valve cover leak, or vacuum leak.

Thanks
Shawn

 

Ok so here is what I did. I found out my intake gasket failed and is causing my car to throw a p0304 (fourth cylinder missfire). I did this by spraying starter fluid (or carb cleaner) around the vacuum lines and around my intake, and it started to rev higher when I found the leak. Good luck.

 

well finally got the misfire fixed, turned out to the the fuel rail and injectors. I put some seafoam in it to clear the gas tank and it clogged up the fuel rail ( after it ruined the fuel pump). Have drove over 20 miles and not check engine light. This is the first time since I bought the car 4 moths ago.