The timing on my truck is jumping all over the place when the truck is idleing. I put a timing light on it and also a scan tool, the scan tool showed that the timing was jumpin from 12 to 26 deg. btdc. My truck also idles very erratically when its cold but the timing problem is all the time hot or cold. Thanks for any ideas in advance

 

My first thought is how old is the timing chain? If it has never been replaced and you have a lot of miles on it, the factory one shows a lot of "slop" when it is worn.

 

The motor itself only has about 50000 miles on it since it was replaced by warranty. Then i put a cam in it and replaced the timing chain when i did that.

 

You may want to verify that there aren't any stored trouble codes on the PCM. There are a number of factors that will cause an erratic idle. As for the ignition timing, it is controlled by the PCM so I would look elsewhere for the cause of the erratic idle issues. The PCM adjusts ignition timing based on various sensor inputs. Something has either failed or is failing and causing the PCM to adjust the timing as you are seeing.

First step is to retrieve any stored trouble codes from the PCM.