how long does a set of spark plugs usually last and how would i go about changing them in an 04 3.7 dak if they do need to be replaced? Also do v6's tend to have a slight rpm jump when idling, and is it usual for an automatic transmission to shift hard at cold temps?

 

Check your owner's manual for spark plug service intervals. Everything you asked here can be found by using the search button.

 

My opinion is that spark plugs should be changed every 15K miles. My v6 idles smooth with slight up and down revs. And yes i would think it would make sense that a cold tranny will shift harder.

 

i'm not sure if its the idle or just the exhaust, but it is quite noticeable though. It tends to mellow out as the engine gets warmer. i know it is suppose to idle rough at colder temps but this is sometimes continuous after long trips.i've never changed plugs on this motor before, do i have to remove the coil packs or what?

 

Im not sure you have a 2004. You have electronic ignition right? Just pull the boot of the spark plugs and get a spark plug socket and take them out. Buy the new ones and a spark plug gapper and gap them to the specified measurement. Thats pretty important. Then just put them back in.

 

make sure you take the rubber boot off one plug take out that one plug put in 1 new plug then put that boot back on then go to the next plug. if you take them all out at once you will mix up your fireing order

 

What idiot will mess up the firing order? Oh yea, I did .

 

I did too atleast I got it on the second try

 

I did the same thing when I replaced my distribuitor cap, taught me to buy a manual though.