I hope someone can help. My '04 Lariat Screw 4x4 has developed a couple of problems (may be related, not sure). The first problem is that the engine seems to be missing at idle (the RPM drops from about 800 to 500, with an audible difference). I think I've narrowed this down to a known cam phaser problem (ssm 18342) thanks to the forum. The second problem is while driving (either in town or at highway speeds). I'm not going to do a good job of describing the problem, but here it goes. There is a sensation, almost like the sensation when towing a trailer and the trailer hits a bump and 'pulls' the truck back a little. But I'm not towing a trailer. I can't tell if it's an engine miss or a transmission problem. It's pretty hard to duplicate, as it doesn't happen all the time, but it was pretty obvious on a trip from Oklahoma City to San Antonio last week. At first I thought it was the highway pavement, as there is a lot of construction between here and there. But now it's doing it in town as well. Any thoughts?

 

3-2 downshift clunk is normal. Annoying, but normal.

don't know of a cam phaser causing a slow/rough idle; all the cam phaser problems I've ever heard about caused an annoyin ticking sound.

Rough/slow idle is usually cured by a PCM reflash...

 

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