I'm trying to diagnose what's going on with my truck. It's an 03 Supercrew XLT FX4 with the 5.4L. I've noticed that when I hit the brakes I can feel a shiver (that's the best way I can describe it) run through the truck. It doesn't feel like it's coming from the brakes, the wheels/tires, etc. It seems to be something engine related or even possibly transmission. I don't think it's the tranny though. I also notice this shiver when I'm at a light. Every few seconds or so I'll feel it while I'm sitting there. Sometimes it comes in fairly rapid succession and others there's a bit of time in between them.

I haven't had a chance to check anything yet so I'm just looking for some opinions on where to start before I go spending a whole bunch of time looking at things that don't need to be looked at. I've only had the truck for about 2 months and it's only got about 42k miles on it. Obviously since it's used, I have no idea what the maintenance history is on it nor how the previous owner drove it. Off the top of my head I'm thinking I should check the IAC, clean the throttle body, maybe take out a couple plugs to see what they look like and check voltage on the COP's. Anything else I should be on the lookout for? Oh yeah and clean the MAF.

A side question: How exactly do I get the PCV valve out on a truck with the cold climate PCV system? It's easy enough to get it out of the valve cover, but is there any special way it has to be removed from the tubes? Or does it just push out?

 

Here are some pics on the PCV, just disconnect the water lines when cold and after relieving the pressure.

 

What you mentioned about the IAC, MAF, t-body clean, PCV are all good places to start. It's now 5 model years old so there may be some buildup in these areas, it's a matter of time anyways before you HAVE to do it. I know the "shiver" but it should be almost unnoticed. If it's during braking, maybe a vacuum line too?

 

torkum, does that clip have to come off before the PCV will come out of the tube? Is there any special way it has to be removed or does it just pop off?

Blue, thanks for the recommendation. Vacuum lines never even crossed my mind.

 

When was the last time the tranny fluid was changed. I had a shiver or shudder just like you described and had the fluid changed in the tranny and now it's gone.

Worth a try.

 

The clip has to come off, just pop it off with a screwdriver.

 

Thanks torkum. Nice truck BTW, almost exactly like mine except mine's an FX4.