I have been working on a 1999 Neon with P0302 AND P0202 misfire codes. Despite having performed numerous tests, the misfire persists. Specifically, I have checked spark (good and strong), checked compression (160psi dry), and installed a new injector. I have also used a noid light at the injector connector to verify ignition voltage (there is voltage) and pulse voltage (there is a pulse). I’m at a dead end - any ideas? Thanks!

 

If you have the P0202 code I would fix that first, That is a fuel injector code. If you have no fuel getting into the cylinder the spark has nother to burn which will give a P0302 mifire code.

 

Thanks very much for your reply to my post. The cylinder is in fact getting fuel - I actually removed the entire fuel rail with all the injectors attached, had an assistant turn the ignition switch, then I verified the presence of fuel exiting the injector. The fuel spray was identical to the adjacent 3 injectors. Seeing as I'm getting fuel, the spark is strong, the compression is satisfactory, and there is no vacuum leak at the intake manifold, is it plausible that the cam position sensor is faulty, even though there is no fault code relating directly to the sensor? Thanks again!

 

Try switching the fuel injector to another cylinder and see if the misfire follows that injector.

 

I will try that, thanks!

 

I switched the #2 injector to cylinder 3 and #3 injector to cylinder 2. I now have 2 additional codes - P0203 (#3 injector circuit malfunction) and P0300 (random/multiple misfires). The P0202 and P0302 codes are still present. Additionally, the check engine light is flashing and the engine idles very rough (as you might imagine). Any insight would be greatly appreciated!