use "sea foam"

 

Some other easy do it yourselfer's;

clean the throttle body using b12 chemtool

Check the #8 cylinder I think that usually may have compression problem if your 5.9 is high mileage.

check the IAC?

replace the tps?





Seen these 4 been mentioned from users with rough or poor idle.

Try these 4 recommendations after you replace your bosch plugs if they are plantium plugs.

 

Motor only has 51K on it. Last one I had, I gave up at 110K and it was still running like the day I bought it. Is B12 Chemtool is available at an autoparts store? What is the IAC and how do I check it?

 

I think the IAC is also located on the Throttle body. Can someone give more insight on this piece?

The B12 Chemtool is a spray you can buy from most places such as walmart. But NAPA and most auto parts shop also carry this spray. I use this all the time to clean my carb's in the past and now use it to clean my throttle body to get rid of the gunk build up. First time I used this on my D, it made a big difference on how it idled and especially how quick the engine was responding to throttle response. So I check and clean my throttle body an avg of every 24k miles or if my throttle body starts showing gunk around the butterfly plates and such. Usually the cause of the quick gunk build up is running cheap quality gas.

 

What is the correct plug gap for the Champion Truck Plugs and the Autolite 3923's?

 

.040 on all plugs for the 5.9 and probably the same for the 5.2

 

I changed the plugs to the Champion Truck Plugs and cleaned up the throttle body with no change in idle. I also experimented a little with the routing of #5 and #7 wires, but that did not change the idle either. So, I am fairly convinced that it is not the ignition. Has to be an injector in my mind. I will change those out next weekend and see what happens. Anyone change out injectors before? Any suggestions for aftermarket injectors?

 

At what rpm are you idling at? You may want to put a quarter turnon your throttle cable tensioner if it seems low.

 

You can check to see if the pcm is throwing any codes? I think there is a user that recently posted a message regarding a injector error and he is having idling issues because of it.

 

There is no check engine light. How do I check for codes? It seems to be idling a little better lately. I have been driving it pretty hard (full throttle off of stop lights every chance I get) and that seems to be helping. There was a lot of hard black (carbon maybe) deposits on the TB and the parts of the intake I could see. Next few tanks I am going to run premium gas and see if that helps as well. Being that it was an 03 with only 51K, it probably sat in traffic quite a bit.