Okay, I did a search and realize this has been talked to death. But in the search there were so many ideas on what the shake/rough idle could be, that I wanted to ask you guys for a "best guess".

Here's the story; I've always been a Chrysler/Dodge guy. In fact, I had bought a new Dakota back in 2001 with the 4.7L that was flawless, sold it after 3 yrs without having a single problem.

A couple of weeks ago I was at the local Chrysler dealer and I picked up a 2006 Dakota SLT 4x4 with the 4.7L and only 32,000 miles on it, for a second vehicle. It had rough idle when I bought it, but knowing Dodge's as I do (or thought I did), I figured it was the plugs or wires. I made the deal with the stipulation that the rough idle had to be fixed. I drove it for a week while waiting for my service appointment. The shake freakin' drove me nuts, but I took it in last week figuring it was an easy fix. They have had it a week, changed the plugs, flashed it and the mechanic had 2 new wires at his station, so he changed 2 at a time trying to get the shake to stop.

I need your help guys. This is a good truck (you don't find too many 06's with only 32k), but the shake is driving me crazy. The dealership is treating me well, they gave me another truck to use while they try to figure this out......but so far, they are stuck. The plugs and flash did nothing. What's next?

 

Did they try the Autolite 3923 plugs (assuming this is not an H.O.)? Those completely smoothed it out for mine.

 

Fuel that is wrong mixture of ethanol or too high in octane can do the same thing.

Spark plugs that are too hot can do it also, I would look into a range colder.

Timing might be too aggressive.

Improper valve seat i.e. the motor heads might need some valve work.

 

I'm making a list....thanks guys.....keep adding (the more options I have, the better)

...and sorry about that Altair - yes it's a 4.7L H.O.

To answer some of the suggestions;

1) They used mopar plugs (any suggestion on a different plug to try, since it's the H.O.?)

2) Gas is 87 octane. In this part of the Country all gas is made by a company called Irving (Esso, Shell, etc, just contract it to them because we're too small of a Province to justify more than one refinery). Gas is pretty consistent, so it's rare that we see a lot of gas related problems anywhere around here

3) Not sure if they have done anything with the timing (I haven't spoken to them since Thursday)

4) Hadn't thought about the valves (ok, now I'm worried....but it's a good point and I still have warranty), since I was so sure it was something simple

Thanks again for the help guys.....and any further ideas, please jump in. It's a shame, it's a good looking truck, great shape, ridiculously low miles and it was a fair price..........but that shake would drive me nuts.

 

Don't the H.O. engines need to run a higher octane? Just a guess here, but could the ECU be pulling the timing back to compensate for detonation caused by too low of an octane resulting in a shake? Again just a guess.

 

gotta run better plugs in the h.o., mopar plugs are junk, also the octane is to low, grab a few tanks of the premiun and see if it helps out, my girls nitro is the r/t with the h.o. 4.o, she was running the 87 and it ran like crap, switrched out to a better plug and priemun, and it now smokes the tires

 

Yeah....the H.O. motor shakes. I put in Iridium plugs and that helped a little. Blew out the throttle body and sensors with (sensor safe) cleaner, not much change. Ran Sea-Foam as directed by the instructions, not much change there either. The biggest solution came by running two cans of Sea-Foam and Premium fuel for a few tanks every now and then. O2 sensors would be my next change.

 

are you guys talking about the shake you get when coming to a stop? I have a slight rough idle but I notice it mostly when coming to a real slow stop just before completely stopped the whole truck shakes like it has a really big cam in it, like it's loping...no, it is not brake related, it's definitely the motor.

 

jkeaton, while the shake is probably the same as what you describe, I'm talking about when the truck is sitting still and just idling (although I'm sure it's doing it when we are moving, it's just not as noticable).

You guys are right about the octane and I just caught the mistake last week (thanks to Robk's comment above) and called the dealer (they still have the truck). When I bought the truck the dealer had put 87 octane in it and I put a tank of 87 in it myself. So as I said, I called the Service manager and told him what was in it for gas, but he is convinced that the computer would allow for that and wouldn't cause this kind of shake. He told me that the shop foreman is convinced now that it is caused by 2 bad injectors and they will be putting new ones in on Monday.

I certainly can't complain about the service, so far they've cleaned everything in the motor, put new plugs in, flashed the computer and now the injectors.......and they lent me a truck to drive. Great service from a Chrysler dealer on a used truck, imho.

Thanks for all the help folks. I'll let you know if it was the injectors.............and obviously, I'll be running premium gas in it from now on.

 

ARRRRRRRRGGGGGGGGGGGG........just spoke to the dealer, the new injectors didn't stop the shake.

When you guys are talking about better/cooler plugs for the 4.7L H.O., are you talking about the Autolite 9322 plugs?