I got a p0300 code what can it be it seems to be runing riche is a 07 pacifica

bad need of a tuneup? like new spark plugs, ?
172 , is 02 rich/ lean warning. this one is low oxy for rich.
this code can just be a victim. for sure , with misfire.
means 02 sensor stuck at rich,
what is water temp in engine coolant, at failure? less than 150F?
could be lots of things.
leaking injectors, bad fuel.
injector sticking> causing misfire.
id use a scan tool and watch all sensor when it fails.
too high fuel pressure.
misfires cold, but only luke warm cold starts not fully cold.

just one DTC, no P0300 or 30x misfire codes, not even P0300 pendings?

Car may be running rich. If the car is getting normal mpg, I would not worry. The codes that indicate poor converter efficiency indicate the converter is wearing out. If that code keeps coming back, replace the converter. If it is getting poor mpg, I would look for something causing rich operation. Possibly a broken fuel pressure regulator or maybe a bad map sensor. Continued rich operation will cause the converter to fail prematurely.

po300 is random miss fire doubtful two O2 sensors bad at one time most likely coolant temp sensor is bad causing engine to run rich this will cause O2 sensors to throw a code(thats what they are there for..exhaust gas temp. and raw fuel) running rich will also fowl spark plugs(=miss fire) P1128 ??

There has to be codes. Well you melted another converter. Your injectors are leaking and the raw gas is overheating and melting your converter Your plugs are black that means way over rich and no codes? If you take the cat loose it puts a code in immediately

P0300....Random/Multiple Cylinder Misfire Detected

so its got a misfire and quickest way out here to avoid a expensive garage visit is to change plugs and Ht leads and see what happens ,HT leads is proper english for fire wires by the way ,see iam learning american ---slowly---

Hi.

P0300 is random misfire, and can be caused by a number of problem. First check if there are more codes stored in the PCM.

If you have only P0300, check spark plugs, distributor (depending on year distribution coils) and high voltage wires from distributor to spark plugs. Those are the most common cause for random misfire.

If distribution is OK, check for ignition problems. A too rich or too lean mixture can result in misfire. Often the problem is not reported by the PCM with a lean or rich code based on the O2 sensors' input.
Check fuel system, injectors, filter and sensors in air intake and air intake itself, vacuum system etc.

Check with particular attention the EGR system, that is a common fault resulting in random misfire. Chrysler Sebring built in the second half of the 90s are commonly suffering from EGR problems (there are several Chrysler service bulletins on this).

P0300 is often accompanied by symptoms such as engine running rough or shutting down. There are more faults, apart the ones listed that can result in P0300.

Regards.

Ginko.

The P0172 code is a rich code most likely caused by the P0300. The P0300 is a random/multiple cylinder misfire code. Replace the plugs and wires.

p0352
Ignition coil B primary or secondary circuit malfunction
p0300
Random/multiple cylinder misfire detected
p03001
cylinder no.1 misfire detected
p0306
cylinder no.6 misfire detected
check you coils and spark plugs
make sure they are in good shape. check you spark plug wires also.

If only code p0300 exists, one bank fuel trim is lean, and the other bank fuel trim is rich, it is wrong camshafts timing. If you mismatch one tooth on timing belt, the result is engine minor misfire and code p0300 is set.
Please remove the timing belt and match up the line marks on the timing belt with the marks on the camshaft and crankshaft pulley. Please pay attention to the arrow on the timing belt point to the front

P1127 Long Term Fuel Trim mult.,Bank1 System too Rich

P1129 Long Term Fuel Trim mult.,Bank2 System too Rich

P1250 Fuel Level Too Low

P1300 Misfire detected Reason: Fuel level too low

P0154 02 Sensor Circuit No Activity Detected (Bank 2 Sensor 1)

P0300 Random/Multiple Cylinder Misfire Detected

P0303 Cylinder 3 Misfire Detected

P0304 Cylinder 4 Misfire Detected

It sounds like there is a lot going on.

Good Luck

Brian