How do I check the camshaft and crankshaft sensors? Also, I already know that it's not firing, but assuming the sensors are fine what might I move to next? What else could keep the engine from firing altogether?

Question edited for clarity.
Question moved to model category.

Crankshaft position sensor location - Colorado Fans

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Dec 16, 2009 - Hey everyone.. do ya know where the crankshaft position sensor is located on our engines? It would be a big help if someone could point me ...

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Timing Chain: Service and Repair
REMOVAL
Tools Required = Crankshaft Sprocket Puller
1. Remove the timing cover.
2. Remove the crankshaft position sensor reluctor ring.
3. Remove the camshaft sprocket bolts.
4. Remove camshaft sprocket.
5. Remove timing chain.
6. Remove the crankshaft sprocket.
7. Remove crankshaft sprocket key.

INSTALLATION
1. Install the key into the crankshaft keyway.
2. Use the crankshaft balancer installer to install the crankshaft sprocket.
3. Install the camshaft sprocket and timing chain.
4. Install camshaft sprocket bolts.
Be sure to align the camshaft and the crankshaft sprocket marks. Timing marks (Number 4 Firing).
Tighten bolts to 21 ft. lbs.
5. Align the keyway on the reluctor ring with the key in the crankshaft.
6. Install the reluctor ring onto the crankshaft until the ring is completely seated against the crankshaft sprocket.
7. Install the timing cover.

Don't know what Wire you are referring to.

I would check the computer for trouble codes first.
Could be a problem in the wiring harness, or one of the components the cam and crank sensors "reads".
And of course you could have gotten a faulty part.
You might be able to take a meter and check each sensor while still on the engine.

The dealer first will need to duplicate the problem, then they will scan the system while it is occurring and decide what is causing the malfunction. Be patient and let them do there job, this may be expensive labor wise if the problem can't be confirmed easily.

p0300 means multiple misfire detected. did the fuel pressure check good? are you getting ignition fire to the plugs from the coils? the crankshaft sensor is in a difficult spot and the connector can be hard to get on sometimes. double check the connector and also make sure the terminals in the sensor didn't get bent while plugging it in.

Maybe the crankshaft sensor or the camshaft sensor. I don't know what brand of car you are working on. Well I guess if it is old enough that would be the pickup in the distributer.

Let's start with the codes.

Po129 refers to barosensor

Po344 is a code for the camshaft position sensor

Po339 crankshaft position sensor

Po340 camshaft position circuit malfunction

Po335 crankshaft POS sensor malfunction

Po122 throttle pedal position

Item 2,3,4,5 relate to each other that s camshaft and crankshaft position sensors. Since both already show a malfunction code, it would be advisable to change.

Sometimes other codes show up because there is a relation but not that the item is bad.

check the pick up coil in distributor. also maybe the crankshaft sensor or camshaft sensor. do you have fire to the coil? if so check fire out of coil. ihope this helps!

On many engines with distributor less ignition systems and sequential fuel injection, a camshaft position sensor is used to keep the engine's control module informed about the relative position of the crankshaft. By monitoring cam position (which allows the control module to determine when the intake and exhaust valves are opening and closing), the control module can use the cam position sensor's input along with that from the crankshaft position sensor to determine which cylinder in the engine's firing sequence is approaching top dead center. This information is then used by the engine control module to synchronize the pulsing of sequential fuel injectors so they match the firing order of the engine. On some applications, input from the camshaft position sensor is also required for ignition timing.
The camshaft position sensor may be magnetic or Hall effect, and mounted on the timing cover over the camshaft gear, on the end of the cylinder head in an overhead cam application, or in a special housing that replaces the distributor (in the case of some of the GM applications). Operation and diagnosis is essentially the same as that for a crankshaft position sensor.  

Re  check the wire harness and the sensor installation to the camshaft sensor in Bank #1 which is where the #1 cylinder is. Good luck and hope this adds some light to you question, keep me posted and be glad to help.

My truck was doing the same thing.... replaced the crankshaft sensor first, truck would still die after about 10 minutes of idleing, it back-fired thru the engine and blew off the back of the intake manifold. Pulled the monifold, reglued end-cap and put back in truck. STILL died after idleing for 10 minutes. Code PO320 kept coming up ( crankshaft sensor) researched it and found a bad camshaft sensor can cause crankshaft sensor to act up and give code for the crankshaft sensor. Replaced camshaft sensor and the truck runs like a dream !!!!!! I believe the Manifold was cracked for a while causing the 1299 code reading ( vacuum leak) the back-fire finished it off! I would check the back of your intake manifold for a leak. The combination of fixing the vacuum leak , cam/crankshaft sensors seems to have fixed the problem. GOOD LUCK!!!