rough idle

[jeepcat]

Hi guys i'm new to diesel. iI have a 97 F-350 Crewcab long box with the 7.3L turbo diesel and auto tranny. On first start it runs smooth but when it warms up it starts to run rough. so far i changed the cps,fuel filter,oil change and temp sensor and I am running some cleaner through the fuel. the truck sat for a few years before I got it. I love it. I wish I had of bought one sooner.

[rolsmojave3]

Which CPS did you use? I've never experienced it, but some complain of a rough idle with a certain color.

[jeepcat]

It is black. I bought it from advance auto parts.

[charlie-2]

{is it this?i got it from php}

My vehicle is having trouble idling after programming. Is something wrong?

It has come to our attention that there have been situations where the vehicle has developed an erratic, unstable or low idle after reprogramming the PCM. The most common cause for this problem is the carbon buildup around the throttle plate which causes airflow issues at idle.

Over a period of time, the PCM is able to automatically compensate for the slow loss of airflow past the throttle plates by either opening the idle air control (IAC) valve more (on cable actuated throttle) or by opening the throttle plate(s) wider (on Electronic Throttle) to increase airflow. When the PCM is reprogrammed, this learned setting is erased. On older vehicles it wasn't a very big problem because the learning curve for the idle was fairly quick and the vehicle could be back to normal speed in about 10 minutes. However, electronic throttle bodies have a much slower learning time which could take weeks or months to fully recover.

So, you have an electronic throttle vehicle. Now what do you do? Actually, there is a really simple fix: Clean the throttle body. In most cases, the throttle body is fairly easily accessible using only simple hand tools. Just remove the inlet tube assembly to achieve access to the throttle opening. Once there, take a shop towel or rag and wrap it around the end of a toothbrush or some other plastic handled device. DO NOT use a screwdriver as you can gouge the side of the throttle body and damage the bore. Apply a little Carb Cleaner or Lacquer Thinner to the towel, open the throttle plate and clean the throttle bore. You will also want to clean the edges of the throttle plate as there will be carbon buildup on there as well. Ideally you will want to remove the throttle body to perform a thorough cleaning, but the above steps should at least help improve your idle quality.

Now, here's an important word about solvents and plastic intakes: the 5.4L F-series, along with a few other vehicles, have a composite plastic intake manifold. For the uninitiated, plastic and solvents DO NOT MIX! Carb Cleaner will damage your intake if you spray it directly into the throttle body. On those vehicles, we STRONGLY recommend you remove the throttle body to clean it or run the risk of damage.

The pictures below are a before and after comparison from a 4.6L throttle body. It is representative of practically any ETC (Electronic Throttle) style unit although manual styles are virtually identical.

[JD3020]

^^ No, because these motors don't have throttle bodies. They have a fly-by-wire throttle system since they are direct injected.

My truck does the same thing. If its already warmed up when it starts it runs nice and smooth for a couple seconds, then it starts to roughen up. Does the tach move any at idle? Mine seems to move up and down just a tad bit, but its barely noticeable.

My problems are caused by worn out injectors, which i am working on replacing. If you have any friends that have a good scan tool, try to do a buzz test and cylinder contribution test. Thats how the dealer determined i had 2 weak injectors, even though we already knew that.

[charlie-2]

sorry!!! i didnt read through it, i just glimsed at it and though it was somthing>