2G Two CEL codes PO304 and P1294, need help diagnosing.

[jeromea]

Last week my CEL came on, and I didn't want to take it in because I've been itching to get a scanner for a while now. So I got my little scanner today, and it threw two codes, one is PO304, and the other is P1294. I checked in the manual and P0304 is cyl. 4 misfire, and P1294 is target idle not reached (within 200).

I got a feeling these two are related, and I went fishing around a bit. My spark plugs/cables seemed fine, and I replaced them about a month ago with a 7mm silicone cable and NGK plugs so I'm pretty sure that's not problem. I don't have a multimeter to check the injectors, but from what I can see nothings melted, and everything is where it is supposed to be visually. I also went around with a can of carb-cleaner looking for vacuum leaks, sprayed everywhere and didn't really get any sudden changes.

Where do I go from here? Could my coil be the culprit?

 

[cliffkemp]

Last week my CEL came on, and I didn't want to take it in because I've been itching to get a scanner for a while now. So I got my little scanner today, and it threw two codes, one is PO304, and the other is P1294. I checked in the manual and P0304 is cyl. 4 misfire, and P1294 is target idle not reached (within 200).

I got a feeling these two are related, and I went fishing around a bit. My spark plugs/cables seemed fine, and I replaced them about a month ago with a 7mm silicone cable and NGK plugs so I'm pretty sure that's not problem. I don't have a multimeter to check the injectors, but from what I can see nothings melted, and everything is where it is supposed to be visually. I also went around with a can of carb-cleaner looking for vacuum leaks, sprayed everywhere and didn't really get any sudden changes.

Where do I go from here? Could my coil be the culprit?

What is your idle? It should be around 800 or so. Check your plug gaps and check pcv valve as well. The valve can get clogged and not function as it should once the car is warmed up and a bad gap or worn plug may have firing issues. Also, check you idle control motor. It is located at your TB and test the voltage on it. Make sure it is within specs. If you have an aftermarket coil, check it as well. The stock coils are good but, aftermarket ones are known to go bad quickly cause people try to open up the gaps thinking they are stronger and they are not. Screamin demon was aweful with this. Make sure your gaps are at or slightly smaller than specs especially if you have aftermarket stuff on your car to rule that out. Check for any rotting hoses as well. A small leak can make a big difference.

 

[96' Eclipse GS]

Always start with the basics, before running around getting conclusions about different parts not working correctly. First off, Have you had any problems before or have the codes been there before? Start with your Code P0304, it is most likely causing your problem with the other Code P1294. You can check to see if your IAC is bad/acting up and then move on.

 

[jeromea]

What is your idle? It should be around 800 or so. Check your plug gaps and check pcv valve as well. The valve can get clogged and not function as it should once the car is warmed up and a bad gap or worn plug may have firing issues. Also, check you idle control motor. It is located at your TB and test the voltage on it. Make sure it is within specs. If you have an aftermarket coil, check it as well. The stock coils are good but, aftermarket ones are known to go bad quickly cause people try to open up the gaps thinking they are stronger and they are not. Screamin demon was aweful with this. Make sure your gaps are at or slightly smaller than specs especially if you have aftermarket stuff on your car to rule that out. Check for any rotting hoses as well. A small leak can make a big difference.

The idle isn't very steady, I just took a look at it and it fluctuates between 900-750-ish. All the gaps on the plugs are set at .044. No problems with the PCV, I replaced that as soon as I bought the vehicle about 3 months ago. Still clicks. As for the coils mine are stock. I checked the secondary ignition from tower to tower, and got what I was supposed to get which is 11.5-13.5 kilo-ohms (I got 13.5). Although when I checked the primary I got goofy numbers. I'm supposed to have 0.51-0.61, and with my ohmmeter set to 2000 I was reading 003? Not sure if that's my problem, or if I'm reading it wrong. I'll check the idle control motor next.

Always start with the basics, before running around getting conclusions about different parts not working correctly. First off, Have you had any problems before or have the codes been there before? Start with your Code P0304, it is most likely causing your problem with the other Code P1294. You can check to see if your IAC is bad/acting up and then move on.

Not really, the only code I had before all of this was a PO455, and the new gas cap fixed that problem. This is relatively new.

 

[96' Eclipse GS]

Double check on the coil, you NEVER want to guess on anything. Start with the misfire and move on.

* Report back with the IAC numbers. * should be between 38-52 ohms.

 

[jeromea]

Double check on the coil, you NEVER want to guess on anything. Start with the misfire and move on.

* Report back with the IAC numbers. * should be between 38-52 ohms.

I got a steady 51 ohms from the IAC. I also double checked the coil, and got weird numbers again. If I measure from B+ to either side with the ohmmeter set to 200 I read 1.7, and if I turn it up to 2000 I get 003. Anything above that is too small of a resistance to pick up.

 

[cliffkemp]

I got a steady 51 ohms from the IAC. I also double checked the coil, and got weird numbers again. If I measure from B+ to either side with the ohmmeter set to 200 I read 1.7, and if I turn it up to 2000 I get 003. Anything above that is too small of a resistance to pick up.

Did you check hoses for cracks or tears? Is the TB stock aftermarket? It is possible that you have a leak and it will not steady the idle. My neon had the same symptoms your car has. You did check the plug wires as well?? If the ohm reading is way off on one or more, it could be the problem as well. Chryslers are pretty picky with electricity. If possible, get a known working coil and try it as they are easy to change out. I still think it is a small leak that is freaking out your IAC. Just big enough to make the idle surge but not that bad. The coil may be part of the problem as well. The only other thing it could be is the MAP sensor is going bad. I know it is a lot to check but, these are the only things it could be. The coil sounds fishy with the results you got. Just to eliminate other things as electrical problems can sometimes be compounded.

Borrow a good known working coil and check for leaks...IE worn out rubber hoses. I know this may sound trivial but, it is real, check the plugs again but, check where it hooks to the wire for burn/worn spots. A bad connection can cause all kinds of misfires that can be random. The air intake temperature and map sensor are one in the same on your car, I believe. If everything else does not fix it, the map sensor is most likely the culprit. It could be any combo of the above. Will take a little time but, it can be fixed fairly easily with time.