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Bere45 01-11-2012 03:37 AM

4.7L Engine Trouble
My 2002 1500 4.7L (126, 000 Miles) threw these codes P0300, P0302, P0305. The engine runs rough and doesn't have much power specially going up any little slope or hill. I changed all eight Plugs. #5 was a little wet and #2 looked a little burnt but I think it was ok still. Took it on a road test but it still didn't run right. So I took it to a shop to get a better diagnostic. They told me it might be my valves that are stuck. What do you guys think? They said all my coils are good and my fuel system checked out correctly.
Any idea how much this will cost me? :4-dontknow:


hemiv8dodgeram1500 01-11-2012 04:36 AM

Warning I do not know if this info is correct but i have found this online for you

"Code : P0300 may also be accompanied by a 301-312. the number after the 3 indicated the misfiring cylinder

Definition : Random/Multiple Cylinder Misfire Detected

Symptom : Check Engine Light Illuminated and engine misfire, may also detect loss of power or hesitation while accelerating

Cause : The engine will set this code when a misfire is repeatedly detected.

Repair : Replace the failed component on that particular cylinder. Most commonly the Coil Pack

Damage if not repaired : Engine damage to the cylinders rings and damage to the catalytic converter from raw fuel not being burned, not to mention the poor performance and fuel mileage.

When you pull the check engine light codes and p0300 pops up you may ask yourself, What do I do now? See if there is an additional code such as p0302. The number that follows the 3 ( 02 in this case) identify's the problem cylinder. So the problem would be in the number 2 cylinder and in most cases can be cured by replacing the coil pack."

Before doing anything wait for an more experienced member to chime in to either discredit or verify this info

snrusnak 01-12-2012 04:58 PM

^what he posted seems to be dead on. I would seriously doubt the shop's knowledge of mechanics if they literally told you "the valves could be stuck". I don't even know how that could be possible, but even if it was stuck open, the piston would contact the valve and bend it and this would be a catastrophic failure (engine would no longer run).

By your description and the codes that are showing up, you have a misfire or multiple misfires. It looks like it is one or both cylinder's 2 and 5. Possibly causes would be coil packs(most common), faulty plugs(you already changed), faulty plug wires, faulty ecm/pcm.

Even though the shop told you the coils are ok, I would question their judgement and question whether they even tested them or know what they are doing because of their valves statement.

BCWhite 01-12-2012 11:50 PM

I got one of those codes once, changed the plugs and reset the computer. Haven't had a problem since.

09nitetrain 01-12-2012 11:54 PM

swap the coils with another cylinder and play follow the coil, if starts to misfire on the cylinder you just moved that coil to, replace coil, also it could be a bad injector. ohm test the injector, should be around 14 ohm of resistance, also using long screw driver, handle part to ear and tip to injecter listen for a tick coming from the injector to see if its opening and closing, any other diag tips just pm

snrusnak 01-13-2012 12:03 AM

09nitetrain give some very good tips. I'd never heard of the screwdriver tip for the injectors...I'll use that I'm sure.

Bere45 01-14-2012 08:21 PM

How do I test my ECU? The truck started doing that the day after I installed my new radio (head unit). Is there any way that could afect my ECU? Sometimes the "check engine Light" blinks but it stays on all the time.

Bere45 01-14-2012 11:49 PM

So, I swap the coils around test drove it and it sounded like I had headers and AFM Cams. So I replace all three (2, 5, and 6) Coils and has lot more power but it's still throwing P0355 at me. And I can still feel so hesitation when I let off the throtle after accelerating.
And another question, was there a mod for the EVAP canisters? because I was trying to change them and everywhere has one that is way small than the one currently on the truck.
I need so help cause I realy don't wanna walk to work again this week !!

snrusnak 01-15-2012 11:51 AM

To reset the computer, unhook the neg battery cable for 15-30 minutes.

icywhite 01-15-2012 12:05 PM

hate to say it bro. it could be a head gasket it is dodge's aklies heel. i have three different dodges and all have blown it. have you looked at the oil filler cap for choc. milk look. since you said one of the plugs was wet

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