Rough idle... Found this forum too late..
 

2001 Durango SLT 4X4 - 4.7L - currently with 66,000 miles


Well.. Lemme start by saying I've been through this forum top to bottom and well.. so far Ive tried this -

1. Took the truck to Tire Kingdom for a tune up (before I found this forum and ya I know now it was a big mistake..) Got scammed into buying a TB cleaning.. Total bill $300.00 And to my glee and amazement they used Bosch Platinum plus plugs :mad: Just an added note, my truck had 64,000 on the original plugs.. so they were black... I was desperate..
2. At this point the truck still idled just as rough as with the chared plugs
3. Repalced IAC and TPS

No difference..

4. Bought some TB cleaner and cleaned the TB myself (after noticing the IAC was black just like the original plugs.

5. Replaced the filter with a K&N drop in and made myself a home made ram air setup (thanks to 2 threads I saw on here :))

Truck ran a lot better.. but still has the rough idle. Also it idles at 500rpm sometimes lower.. Isn't that a little low? Its actually stalled before because of this.

I've taken back to tire kingdom and complained that they used platinum even when I asked them not to.. only to be told it couldn't be the plugs that it has to be something else.. of which the guy starts naming off everything from harmonic balancers to motor mounts ect.. I should have known to walk away when he tried to sell me a spark plug wire set even when my truck doesn't use them...

So.. my next option is to probably get the platinum plugs out of the truck and put in some champion OEM's but, is there anything else I could be missing that would cause the rough idle besides the platinum plugs?


One other thing I noticed when the plugs were replaced at Tire Kingdom.. The tech had to get the computer out and plug it up to the port inside the truck.. Struck me as odd unless it starting giving error codes. Although it doesn't give codes now..

As you have the 4.7 engine, users here have used the Plat's and did not have the issues that the older 5.2/5.9's have with plats.

I don't know much about the 4.7's other than they have a totally new type of ignition system that is supposed to be alot better than the older style used on the 5.2/5.9's. One of our fellow 4.7 users should be able to answer this for you. But wouldn't hurt to go back to basics before Tire Kingdom made the changes. Try going back to OEM plugs, gap them properly and see if this solves your issue since you have already addressed the IAC and TPS.

You mentioned the tech had to remove the computer and plug it up to the port side of the truck? what does this have to do with replacing the plugs????

Exactly! :confused: I have no idea what he did unless the truck started giving codes and he somehow cleared them.. But then wouldn't they come up again?

Also, another recommendation is to have your fuel injectors cleaned to see if this helps. Most reputable dealerships charges around $120 for the injector cleaning. I have mine cleaned around every 45-50k.

Seafoam is about $9 bucks a can and does a good job, but I am against any additives so use at your own risk.

They can read what the engine is doing while running. But if it was shut down like you are saying then this shop and (given what was staited) doesn't know a red light to a green one. Sounds like they bent ya over the olde stool....

You have done everything so far as I can guide you. Pull those plugs out and install chamion OEM copper or champion truck plugs.

So for the Seafoam.. I've read that you have to split it into 3 parts. 33% in the gas, 33% in the oil and 33% into the intake.. So.. the question is how to I get it into the intake?

I'll be putting in a new set of champion coppers this weekend.

Just put it in the gas tank.

If you want to clean the crank case then you can put some in the oil and pull it out pretty quickly. Also IF you do this I suggest a cheap filter and oil for a 100 mile flush after installing it into the crankcase. As for the intake, people will put a vacuum line into it and slowly allow it to go into the intake usually from the brake booster line. This is where you get the split.

People will run the fuel low and dump the rest into the tank for the fuel system cleaner.

Like I said, I don't like to use them but a lot of people do and if you are going to use them then (Seafoam is sold at places like Auto Zone) that is what I would use.

Well..


I did the seafoam treatment. (gas and intake) Also installed the Champion OEM coppers. (Did these about 3 days apart) After putting in the Champion plugs, the trucks idle and response was alot better. Although this morning driving into work the truck starting doing the same thing again. RPM's drop below 500 and it feels like its gonna stall. This only lasts for about 10secs and then it seems to recover, althout the RPM's still are right about 500 after this (usually it idles a little above 500)


So at this point, with no codes and all i've done I have no other clue what could be causing this. Once I hit the gas its fine, it only occurs at idle. :(

Replace the IAC sensor.

Other than that maybe a TPS sensor.

I don't wanna beat a dead horse but this is written in a service manual pdf for durangos..

DESCRIPTION
All engines use resistor type spark plugs. 4.7L V-8
engines are equipped with “fired in suppressor seal”
type spark plugs using a copper core ground electrode.
Because of the use of an aluminum cylinder head
on the 4.7L engine, spark plug torque is very critical.
To prevent possible pre-ignition and/or mechanical
engine damage, the correct type/heat range/number
spark plug must be used.

only use the specific plugs=I've seen peeps usin performance plugs and they caus hell and havoc...as for Seafoam=the best stuff out there for maintaning an engine and one other note=injector tip erosion due to using methanol=don't put any dry gas etc with large amounts of methanol=the injectors get fubarred and then spray pattern loss causes performance and fuel economy losses not to mention they may start leaking causing wicked problems especially in the older 98-99's...I'm already pricing a new set for my engine and hope to get em soon...One more thing the ignition coils=no MSD Blasters...Accel makes one that will match up......Damn now I really need a beer...