Car: 2005 Chrysler 300C
Join Date: Jan 2010
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P0300 - '05 300c
I've been intermittently having the classic hesitation/stalling/no power issue for several months now. My 'C' has 130,000 kms on it and is religiously maintained. It kept throwing a P0300 code at me that would disappear after 3 successfull "trips". Only this code, nothing else. I read through the TSB's and all associated literature (this site is awesome) with regards to this code. I also read about the SeaFoam product and decided to give it a try for $15. After trying the spray shot SeaFoam into my 4 cycle lawn mower and immediately found a noticable difference in performance and overall quieter operation. I could actually hear the engine "smooth" out as I sprayed SeaFoam into the carb. So into the Hemi she goes. I removed the engine cover and used the large vacuum hose on the right side of the intake runners. I poured about 1/2 a 16 ounce can slowly into the vacuum line. The Hemi stuttered but kept running. Shut down and wait 8 minutes. Fired her up and rev to 4500 or so - the smoke was wild but the Hemi ran fantastic and throttle response was markebly improved. I put her in first and drove about 2 kilometres maintaining about 4500-5000 RPM. The smoke eventually petered out. The Hemi ran fine, but still stumbled when punched. I drove home, about 15 kilometres, and pulled the codes again using the key acc/on method. Now I get, P0016, P0300, P0315, P0335, P0339. All, except P0300, point directly toward the crankshaft positioning sensor.
P0016 - crank/cam timing misalignment
P0315 - no crank sensor learned
P0335 - crank position sensor circuit
P0339 - crank position sensor intermittent
SO, today I will pick up a crank sensor from Chrysler and install it. I understand they are about $30. The sensor is located behind the starter motor. Standby for results.
NTF: I also ran SeaFoam through my 44,000 mile '95 Ford Thunderbird Supercoupe. This car is pristine and has been babied since new. It also feels "better" (throttle response, quieter, smoother etc.) but it did not smoke a fraction of what the Hemi did. The smoke is caused by loosened carbon deposits being burned off. So the Hemi did have quite a build up of carbon regardless. At this point, I have to support the SeaFoam product. Three engines with all three showing marked improvement. I understand pouring 5-7 ounces into your crankcase about 100 miles before an oil change will breakdown carbon, varnish and oil deposits that will be drained away. Again, I will try this on a 4 cycle lawn mower. Fresh oil, then a SeaFoam treatment, cut the lawn and then drain the oil for a visual. Standby once again.....
Last edited by Hosehead; 06-14-2010 at 07:55 AM.