I have a 2002 Dakota 4x4 w/ 4.7L auto, I am getting a P0301 code and it takes usually multiple cranks with extended crank times to get the engine to turn over, once it does It has a rough idle. Usually the idle is a little worse when in drive than in park, and for some reason its usually easier to start the colder it is sometimes when it is really cold outside it will just start right up..... I have already replaced the Ignition coil and spark plug in #1 cylinder, and replaced PCV valve. once it gets some throttle the roughness of the idle seems to work itself out. I bought a can of seafoam but am not sure if this will do anything to help the situation or not, any help would be greatly appreciated Thanks!

 

Just because its not setting misfire codes for other cylinders does not mean they aren't misfiring. Also, are the plugs in good shape? Do you have a respectable plug in there, as in not some Bosch 4 prong dopplar radar super plus plus satellite uplink spark plugs? They only plugs I would recommend is the OE style copper champions or an autolite compatable

 

could the spark plugs be causing the long crank time?

 

A long crank time after the car sits a while could be from a loss in fuel pressure over time. Could also be a loss of the cam sensor signal. The engine will start without a cam signal but has an elongated crank time while the pcm tries to figure out what is what based on the crank signal alone. But this would almost certainly yield a DTC. To answer your question; yes plugs can cause a long crank time, but what is "long" 5-10 seconds? Ive seen cars come into the shop that recently had plugs replaced in a tune up and the car has serious driveability issues, including long crank times, from people putting "fancy" plugs in the car that just has characteristics that the ignition system doesn't work well with. This seems especially true with dodge/chrysler/jeep products. For example a 5.9 ram that had autolite iridium plugs in it would have bad misfires in almost any scenario other than WoT and spat out P0300 multiple random misfire codes within a few mins. The gap was perfect and the plugs had less than 150 miles on em. Swapped in new OE champion copper plugs and HUZZAH ran like a gentle cam in block kitten.

 

so then should my next step be replacing all spark plugs?

 

you said you replaced the number one plug and coil right? If you're still getting a cyl 1 misfire code after that, either you replaced the wrong cylinder's parts or theres some other issue. If I were you, yes I would replace all the plugs with the OE replacement champion. 15 dollars later lets see if your problem still exhists.

 

Let me ask you this, I see where you truck is a 4x4, have your been off-road with it lately? Washed it? got it wet at all???

 

ok, so i replaced all of the plugs and some of them were horrible looking.....the truck does idle better now and i lost the cel light for 1 day.... b ut it is now back and i get a little bit of a rough idle just enough to be annoying that i know its there.... and no i havent been off roading with it lately.

 

plus I gained about 2.25 mpg after changing the plugs always a bonus

 

Ok so, replaced the plugs with coppers, and seafoamed yesterday.....problem is still there any ideas? Maybe an injector problem?