i have a 2007 dodge ram with 5.7hemi. its got the multi displacement crap on it. anyway when i first start it it shakes and makes some loud knock sound from motor. not a fast nock just every so often. it does this for about 10 min. and when its warmed up doesnt make a sound or shake. idles smooth at that time. the code said cylinder 6 misfire. any ideas. dealers tryn to tell me i need valve job,heads,lifters. they also said they looked at valves and everything looked fine but called chrysler and said i need all that. so its not covered since i have 50,000 miles so would like other opinions. thanks alot.

 

Did you buy the truck in early 07? I have a truck built 06/11/07 and bought 08/23/07 and it has the lifetime warranty. That should be covered under powertrain huh

 

not sure ill have to check. im leasing it though so they said 3 year 36000. said absolutely nothing was covered. didnt buy service warranty. didnt think i should have problems in 3 years. at least nothing major

 

jus have a hard time believing thats the problem

 

I read on another forum some time ago (maybe a year or so) that the '06s (first year of MDS) had a pre-detonation problem specifically on cylinder #6, and could be traced back to the use of 87 octane gas on a regular basis. Of course, since the manual states that 89 is recommended, but 87 is ok, I'd say it's a design problem.
Don't know if it applies to you, but you may be able to use that info and do a little research to fight them on it.
Don't know why a leased vehicle would not have a lifetime, so check into that as well.

I've searched the other forums I am on, can't specifically find the thread, but I know I've read it...

 

thanks hammer. i always used 87. maybe thats it. is there a fix for the problem im having? or do u think damage is done already? il look into warranty but according to dealer there is nothing

 

Only a compression test will tell you for sure. In the mean time, I'd start using 89 Octane, at least.

I'm trying to find that thread, but I'm on about 4 other Dodge/Hemi related forums and I don't remember where I read it. Searches for "Cylinder Misfire" is popping hundred plus page hits on the one I was thinking it might be on.

 

thanks. also i appreciate u lookn. im layed off and a couple thousand to fix what they say is wrong jus isnt gona happen anytime soon.

 

does anyone know how many psi each cylinder should have in the 5.7hemi. dealer told me my 6 cylinder had 120lbs and 4 cylinder had 150lbs