Cylinder Contribution Test Failed?

[Dave]

The reason I asked is the gray CPS was known to cause CCT failures.

[Jake]

If you've got the gray CPS you may get something that looks like this.

[nexttimeforsure]

Jake - That would answer all the questions. As I say, I can't imagine the engine running any better. Thanks a heap!

[Jake]

Your welcome!

[MSB6]

Let me chime in a little on my problem. I have an early'99 7.3 a/t with 130,000 and my truck runs fine going down the road. When you start it up cold in the morning it runs fine and idles smooth. After it has been completely warmed up, aprrox 20 miles to work, it has a little bit of a rough idle. It seems like most peoples trucks are the exact opposite, rough idle when cold, mine is smooth when its cold. I have a gray cps installed but a black one is on its way via ebay this week. I took it in to the dealer and was convinced #8 inj was bad. It was failing the cct and also failed the bench test. After the inj replacement it was still failing the cct about 1 out of 3 times. Popped in a new gray sensor, no change, put in new icp sensor, no change. Oil change, and fuel filter just changed as well. Here is another thing it does. My regular idle is about 750 rpm, if you rev it to aprrox 1000-1200 and let off, the idle will drop to about 500, stumble just for a split second and then back to 750. Does this sound right????

[HVAC SuperTech]

sounds like mine. hahaha. its been that way since I bought it.

[SCUFFY828]

Originally Posted by MSB6

Let me chime in a little on my problem. I have an early'99 7.3 a/t with 130,000 and my truck runs fine going down the road. When you start it up cold in the morning it runs fine and idles smooth. After it has been completely warmed up, aprrox 20 miles to work, it has a little bit of a rough idle. It seems like most peoples trucks are the exact opposite, rough idle when cold, mine is smooth when its cold. I have a gray cps installed but a black one is on its way via ebay this week. I took it in to the dealer and was convinced #8 inj was bad. It was failing the cct and also failed the bench test. After the inj replacement it was still failing the cct about 1 out of 3 times. Popped in a new gray sensor, no change, put in new icp sensor, no change. Oil change, and fuel filter just changed as well. Here is another thing it does. My regular idle is about 750 rpm, if you rev it to aprrox 1000-1200 and let off, the idle will drop to about 500, stumble just for a split second and then back to 750. Does this sound right????

i dont really see a problem, without looking at it , and monitoring data to see if something is a little out it would be hard to say