How To: Replace Cam Position Sensor (3.5)
You do not have to remove the manifold on the 3.5 engine to replace the cam timing sensor. I've done it twice on my '04 Intrepid SXT.
Remove the bolts that secure the right side and center of the manifold on its outer periphery. Use a pair of wrenches or a screwdriver to carefully flex the manifold up. It does not take much, maybe less than half an inch. Use a large screwdriver or pair of wrenches to hold it in the flexed position. The trick is to be gentle and slow. In colder slimates, you may want to bring the engine up to operating temperature first, to make the plastic of the manifold more pliable. Here in Houston, TX, you don't have to warm up anything. It's already hot.
Remove the nut that secures the timing sensor. Often, these are almost 'glued' into place by accumulated road grit, so you may have to turn it and fiddle with it to 'break' it loose. When you have, begin levering it upward, out of its hole. It will still hit the underside of the manifold. All you need is the least little bit of extra lift, and the sensor will pop right out.
Putting the new one in is the same thing, in reverse. You may have to fiddle with it a bit, but if you had room to get the old one out, you've got room to get the new one in. You may have to flex the manifold up just a little more, since the new sensor will have the little paper spacer on it. But it will only be a very tiny amount.
OK, so you have the new sensor in, and are ready to remove the wrenches, screwdrivers, etc you have wedging the manifold up. The trick is, again, to do it slowly and gradually. Do not just pull them out and let it snap down, that may cause a crack in the palstic manifold. Instead, lift all but one temporary support item out, and then let the manifold slowly relax back to it's normal position.
Re-attach the manifold support arms. Adjust and tighten the cam position sensor. And you are back on the road.
The key to it all: be slow, gradual, deliberate, gentle, and kind when flexing the manifold, and you don't have to flex it very far.