Rep Power: 256

I just pulled my codes and reset the ECU this morning around 4am. Anyways, my code reader showed 300, 301, 302, 303 and 304. I know this indicates a misfire in all 4 cyl. and random misfire throughout. The car does have a slight shiver to the engine, although it is barely noticeable. Other than replacing my plugs since the car has 100k, what should I look for as far as fixing this myself. Some people have related the cam sensor and the crank sensor for ignition timing. Just seeing if anyonw else has run into this problem.

 
Rep Power: 256

Bringing up the dead again. 4months have gone by and still no luck on this cel light. Since my last post I have replaced all of the coils, replaced the plugs with iridiums, cleaned my AEM filter, checked all of my vacuum lines and still no luck. The light comes on some days and doesn't on others. I still average 36 mph to the gallon, so I am puzzled where to go. I have power puleys, underdrive, AEM V2 intake, VAFC-2 (taking out this weekend) doesn't work in my car, Header and mandrel bent exhaust with Apexi dunk rear. I have a 5pd EX and have no idea on what to look for next. I read that someone said the head gasket led to their misfire, but would you see traces of water in your oil?

 
Rep Power: 256

Could a mod please move this for me, apperantly this was posted under the wrong forum initially. Thanks

 
Rep Power: 452

those codes indicate you have a random misfire occuring. P0300, 0301, 0302, 0303, and 0304 are all misfire codes. You are getting all of them because you are misfiring somewhere. Did you have any other DTC's with these? If so, you need to troubleshoot those first. Misfiring codes are sometimes hard to find. Its kind of a matter of checking one thing after another. Since you already replaced the plugs and coils and the problem is still there, you may have a failing injector, may have a bad connection at an injector, or a coil, faulty wiring somewhere, low compression caused by a mechanical problem or faulty PCM. If you want, I can help you go through the procedure to check all of this. there is a specific procedure from the manaul, so if you have a DMM, that would help.

And yes it is possible that you could have a failing cam or crank sensor, but both of those will bring up another trouble code and that why I ask if there are other codes along with the misfire codes.

 
Rep Power: 256

Only the mis fire codes are the codes that I have received from the OBDII. I also do not have a manual as of yet. If I wanted to check the resistance on the injectors, what resistance number should an injector display? The only thing is there is no longer a stutter or shiver to the engine since replacing the plugs. So bad fuel delivery seems somewhat vague in relation to the cel codes. If your willing to take the time and walk me through some things to check then by all means I truely appreciate it.

 
Rep Power: 452

Ok, since there is no longer a hesitation or shutter, is the check engine light still on? Also can you tell under what conditions the misfire happened? Like the shutter came at low RPM, or only at idle, or only at high RPM?

First thing you need to do is check all the connections at the coils and at the injectors. I would disconnect the battery, then pull each connection at each injector and each coil and physically make sure all pins are nice and tight and there is no corrosion. Since you are randomally misfiring, the computer may see this misfire going from cylinder to cylinder from a outside cause, possibly too much fuel to burn, not enough fuel, vacuum leaks. Let me know from this, but if the code is not there anymore and there are no symptoms, there may be no misfire anymore. Alot of times it helps to diagnosis it in the act. It is alot harder when there are no symptoms and no light anymore. But if it is still there, I am willing to guide you through the diagnosis process.

 
Rep Power: 256

The rough shiver was during idle, but is no longer present. I will say that there seems to be a flat spot in the acceleration. between 3500-4300 rpm, there just doesn't feel like a smooth pull transition when getting on it. In reference to the codes, sometimes the light is on, then other days it stays off. It's like hit or miss with the cel, although it is still on right now. I will get to work on checking all of the connections tomorrow.

 
Rep Power: 452

I would go ahead and check all the connections, then if those are fine, erase the code again. Then when it does come back, immediately start diagnosing it. Check the fuel pressure and see if it is out of specs. if it is ok, start checking individual fuel injectors and wiring issues. If those are ok, you may need to hook up a scanner to the car and record the freeze data from the when the code was stored. there may be another issue with another system on the car that is intermittent causing a misfire and not enough to trigger a seperate trouble code. Good luck though

 
Rep Power: 256

What it basically boild\s down to is that I need to take the car to a shop that can hook up my car and diagnose it is what your saying. I went throught the connections at the coils, checked the injector wires and everything seems to be in working order. I think that I am starting to hear a valve beginning to tick, although it's very faint. I wonder if my valves might be out of adjustment. I do have 107 on the motor and not sure if the previous owner ever had the head adjusted.

 
Rep Power: 452

well one of the recommendations by the manaul says that if the misfire occurs at high RPM, under load, or under various other conditions, to also check the valve clearance. like I said, random misfires are hard to locate. if it was a regular miss, it would be easier, but these are difficult. I would maybe suggest doing a valve adjustment. if the clearances are way out of spec, more then likely that is the problem. try that first. make sure you do it while the engine is cold, otherwise you could incorrectly adjust them.

You dont necessarily have to take it to a shop, if you had access to a good scanner, you could check for freeze frame data. or possibly try and catch the data as the misfire occured. otherwise, yea a shop would have to do it.