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what does a p0440 and p0441, i also have had a p0300 , so i changed the coil,plug wires and plugs, as per a friend that works mainly on mopars for many years, the engine misfire went away for a few miles, roughly 40 or 50 miles and misfire come back, it would miss at an idle, turn on ac it started missing real bad, i can take off real fast and engine missfire goes away thru all rpm range, but if i level off ,steady speed miss fire comes back a little, . my friend said maybe i got a bad coil, so i went back to adv---- auto, pulled the intake back off, and replace coil ,wires ,plugs again, car run fine for a few miles again,. now the missfire is a little worse, and i checked the codes again ,now i have the codes listed above, does any one have any ideas, im a decent mechanic, old school, but i can replace parts ok , just not up on all the new electronic stuff, and i dont really want to pay the dodge dealer to play guessing games with my car, im pretty good at that myself, oh this might help, ive got a 2003 pt cruiser ,automatic ,non turbo, any ideas any one,,, thanks johnny
 

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Welcome to Allpar. P0300 (multiple cyl misfire) can be commonly caused by plugs, wires and coil, but like any fault code should be diagnosed first before just replacing parts...twice.
It can be ignition, fuel or mechanical related. There was a spark plug change for some 2.4L engines:
http://oskin.ru/pub/chrysler-dodge/manuals/Temp/TSB-08-008-04.pdf
The correct Mopar/Champion Coppers or NGKs are recommended as other brands or types may cause problems.
P0440 and P0441 are evaporative emission faults that may be related to each other, but not to the misfire.
NVLD stands for Natural Vacuum Leak Detection. It took the place of the older LDP-Leak Detection Pump. Go by your underhood emission hose map to trace the evap vapor flow.
Review some possible causes and then use the process of elimination to get closer to the root cause. Shared causes between different problems are the most likely cause.
Find out what you can with the tools that you have. A good detailed (factory) service manual may be your next best investment.

P0300-MULTIPLE CYLINDER MISFIRE
When Monitored: Any time the engine is running, and the Target Learning Coefficient
has been successfully updated.
Set Condition: When more than a 1.8% misfire rate is measured during two trips. Above
3000 RPM 1 trip less than 3000 RPM 2 trip.

POSSIBLE CAUSES:

INTERMITTENT MISFIRE
VISUAL AND PHYSICAL INSPECTION
IGNITION WIRE
ASD RELAY OUPUT CIRCUIT (COIL)
ENGINE MECHANICAL PROBLEM
IGNITION COIL
COIL CONTROL CIRCUIT
SPARK PLUG
CHECKING FUEL PRESSURE
FUEL PUMP INLET STRAINER PLUGGED (LEAN)
RESTRICTED FUEL SUPPLY LINE (LEAN)
FUEL PUMP MODULE
CHECKING FUEL LEAK DOWN (CHECK VALVE)
FUEL INJECTOR OPERATION
ASD RELAY OUTPUT CIRCUIT (INJECTOR)
FUEL INJECTOR
INJECTOR CONTROL CIRCUIT
PCM (IGNITION SYSTEM)
PCM

P0440-GENERAL EVAP SYSTEM FAILURE
When Monitored: Engine Running. Fuel Level greater than 12%. Ambient Temperature
between 4°C and 32°C (39°F and 89°F)
Set Condition: The PCM does not see the NVLD swtich close during the medium/large
leak test. The PCM then will increase the vacuum supply to the EVAP system by
increasing flow through the EVAP Purge valve. If the switch does not close with an
increase in vacuum an error is detected. Two Trip Fault.
POSSIBLE CAUSES:
VISUAL AND PHYSICAL INSPECTION
EVAP PURGE SOLENOID VACUUM SUPPLY INSPECTION
EVAP PURGE SOLENOID
NVLD SWITCH OPERATION
GROUND CIRCUIT OPEN
NVLD ASSEMBLY
NVLD SWITCH SIGNAL CIRCUIT OPEN
EVAPORATIVE EMISSION LEAK DETECTION
PCM
P0441-EVAP PURGE SYSTEM PERFORMANCE
When Monitored: Cold start test. Engine Running. Small Leak Test Passed.
Set Condition: The PCM activates the EVAP Purge solenoid gradually increases to
maximum flow. During flow, the PCM looks for the NVLD switch to close. If the PCM does
not see the NVLD switch close at maximum flow an error is detected. Two Trip Fault.

POSSIBLE CAUSES:

NVLD SWITCH OPERATION
CHECKING EVAP PURGE SOLENOID FUNCTIONALITY
EVAP PURGE SOLENOID VACUUM SUPPLY
VERIFY NVLD OPERATION
TEST A
POSSIBLE CAUSE
 

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Hi guys!

I have a 2001 PT Cruiser base (very early production - April 2000) with a 5 speed. A couple of months ago I got a P0304 code, misfire cylinder #4. My mechanic replaced the coil, plugs, and wires. Everything's been fine until yesterday when it began to idle rough. It wasn't until I pulled out to go uphill and hit second gear that the check engine light started flashing and it started trying to shake itself to death. I got off the road, shut it off, and when the ignition was turned back on to get the code, the check engine light was off! It started fine but ran rough and definitely didn't like more than about half throttle. I drove to work this morning, still running rough but no light. Came out this afternoon and as soon as she fired up I get the flashing engine light! This time I got the code P0300, multiple cylinder misfire. It started OK, and the light stayed on and I'm able to drive it, albeit a bit slowly .I've read that it could be anything from the EGR valve to the fuel pump. Since the coil, wires and plugs are new I'm ruling those out for the moment. So....any ideas?
Jim
Thanks!
 

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The vehicle really shouldn't be driven with a flashing 'ck eng' light. You could possibly damage the cat.
You have a misfire that needs diagnosis. It can be spark (electrical), fuel or mechanical.
Even if the light is off, the fault code and the freeze-frame information is still there as long as the battery isn't disconnected.
 
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