im going to take my truck in to have the rough idle looked at, are there any things i should tell the auto shop to look at specifically? im getting this done for free from an auto shop i take my other truck to all the time and not the dealer auto shop because they keep telling me that 'its the nature of the 4.7l' but it has a noticeable shake..

 

The ol' 4.7l rough idle problem .....

How many miles do you have on the truck?

Honestly, youre better off buying parts and having them installed rather than asking someone to find it, as they wont most likely. (Not to be negative.) But most of the time if theres not a code, they arent going to be able to pinpoint a problem that could be caused by anything from a sensor going bad, to a small vacuum leak, to a faulty coil, to dirty injectors, or bad O2 sensors. First thing I would do is swap the spark plugs for a range colder. If that doesnt work and you are close to the 100k mark, I would do new upstream O2 sensors. Also check if the IAC valve is dirty, along with the MAP sensor.

Good luck finding it. Ive chased mine for 2 years and still no luck, but I havent swapped the O2s yet. Mine idles pretty rough, but I cant seem to figure out what is going on. For now, Im just running it until the problem becomes big enough to throw a code.

 

Have them clean the IAC sensor. That fixed my idle problem.

 

it has 83k on it, what would be the order of parts to buy and replace on the truck starting with the cheapest?

 

IAC...02 be where i would start...also clean the throttle body as well that can cause problems too!

 

I would personally start with replacing the sensors in the TB and cleaning that out since it something you can do yourself. Remove the TB from the engine, and remove all the sensors from the TB. Use TB cleaner and go at it until its clean. I would replace the IAC and TPS. I ended up buying 2 IACs when I tried fixing my idle issue because I went with Mopar the second time, but it turns out BWD makes the same IAC that Mopar sells ..... so now I have 2. Lol. Definetly buy a TPS from Mopar though. I put a BWD and Airtec/Wells on my truck and both get somewhat touchy, although they both were better than my stock TPS. The Wells sensor gave me the least problems and is on the truck until my Mopar sensor comes in the mail.

Next, I would replace the MAP sensor. For this one, I just went with one from RockAuto (Standard is the brand name) and it ended up costing me about $25. It didnt fix my rough idle but it didnt make it any worse, so Im not sure if you should buy a Mopar sensor for that or not.

Also, swap your spark plugs out for either stock copper cores or go for the Autolite 3923s or NGK V-Power 4644s. You may want to try this before buying new sensors as spark plugs are only $20.

And last, look in to getting the O2s replaced. I couldnt reach them myself, so I ended up returning the ones I bought and I am waiting until spring. You will either need them professionally installed, or you would need to drop the exhaust after the manifolds .... atleast thats the only way I see possible to replace them.

 

i tried those autolite 3923's. maybe ill switch to the ngk's and see if that helps. also i dont have a ton of experience when it coems to working on car engines, but i can figure most stuff out if i get somewhat decent instructions/directions.

what is the difficulty rating on these small repairs

 

Here's the procedure from the manual

WARNING: THE EXHAUST MANIFOLD, EXHAUST PIPES AND CATALYTIC CONVERTER BECOME VERY HOT DURING ENGINE OPERATION. ALLOW ENGINE TO COOL BEFORE REMOVING OXYGEN SENSOR.

1. Raise and support vehicle.
2. 4-Sensor System If removing the right-upstream (2/1) sensor, remove the right-front tire/wheel, and then remove the plastic inner fender liner.
3. Disconnect wire connector from O2S sensor. CAUTION: When disconnecting sensor electrical connector, do not pull directly on wire going into sensor.
4. Remove O2S sensor with an oxygen sensor removal and installation tool.
5. Clean threads in exhaust pipe using appropriate tap.

INSTALLATION
Threads of new oxygen sensors are factory coated with anti-seize compound to aid in removal. DO NOT add any additional anti-seize compound to threads of a new oxygen sensor.

1. Install O2S sensor. Tighten to 30 N-m (22 ft. lbs.) torque .
2. Connect O2S sensor wire connector.
3. 4-Sensor System: If installing the right-upstream (2/1) sensor, install plastic inner fender liner, and right-front tire/wheel.
4. Lower vehicle.

 

couple of questions, where and what is the EGR valve?
where and what is the IAC?
and i am looking to do this sea foam treatment this weekend but wondering what are the best places to pour it in at and if anyone has had positive results with it?

 

The EGR is located behind the number 7 cylinder on the drivers side. It is controlled by the solenoid that is right above your brake booster, and it allows unburned gasses from the exhaust to be introduced to the intake to be reburned and reduce emmisions .... atleast thats how I understand it.

The IAC is the bottom sensor on the drivers side of the throttle body. It is the big round one. If you need a sensor for it, I have one from Mopar with less than a few thousand miles on it. I bought a second new one when I was trying to solve my high idle problem so I would sell it for a fair price to help someone out.

For the seafoam, I have done it. Its a "eh" kinda thing for me. I hate dumping additives in my engine. Best way to treat an engine with seafoam is to remove the brake booster line and slowly pour it down that with the engine running.