I have a 2003 Dodge Neon that started getting engine light in Code is P0303 several months ago. I have replaced the plugs, wires, spark plugs, coil pack. Swapped out the fuel injector between #3 and #4 cylinder. Compression at 50 lb on the cylinder not great but within spec. Just tried t smog after resetting the computer passed with flying colors but after monitor were set error came back with 10 miles. Any idea how to proceed?

 

Your first problem is that you are posting a problem in the New Members section. This is supposed to be a place to introduce yourself and maybe talk about your ride.

You'd likely be much better off if you'd post about a problem that you are having in the section of the forums that applies to your car (ie: the Neon section). That way, the most people that own / have interest in the same car as you will see it.

Now, about your car.... If you are getting 50 PSI compression in the #3 cylinder, you likely have a mechanical problem such as a bad / burnt valve, a bad set of rings, leaking head gasket, etc... It'd really help to see if the compression is in the same range with the other cylinders. If you are running something like: 130-125-50-132 then it'd be obvious where your problem lies. Please check the compression in all of the cylinders and then post back with the results.

-Ken

 

Thanks for the information. In checking all the cylinders best case was 70 worst was 50 also had a 60. According to manual should be 170 to 220 range with minimum 25%. So figured 50 would be acceptable. After reading other postings beginning to think I need to check the cam? I knwo have the engine light on hard with error code P0300 and P0303. Will re-post in the Neon area if I can figure out. Again Thanks

 

If the spec says 170 - 220 all of your numbers are very low. Let's hope it is just your compression gauge or you are using it wrong.

I'd ask in the Neon forum about what those error codes mean and what the likely causes are. I don't think that most people who can help you will see this post in the new member area.

I'd start by looking into the error codes and I'd also look into why your compression numbers are so low.

-Ken

 

I will pull the valve cover this weekend and doubel chek the compression. I have posted the same in the noen forum.