my truck starts fine every morning but after i get where i gonig and go to leave my truck dont want to start. i replaced the lift pump about a month ago the fuel pressure is about 13 to 15 right now and the problem hasnt changed any. i went and had it put on a computer and it said something about a oil sensor that cools the oil to a certain temp or it can cause the truck to not want to start. so i guess what im asking do you guys think thats what it is

 

If it where me depending on the price of the sensor id probally try it just to eliminate it as a option.

 

more then likely its the VP44 when the diaphragm goes it causes a hot start issue, there is no sensor that cools the oil on a 01 btw
also pull the codes your self and let us know what you get.

to pull the codes turn the key on off on off on (no start ) watch the odometer and write down the code that show,

 

After shutting the engine off and the lift pump stops running, the fuel supply pressure should drop rapidly back to -0-psi. With a hard start concern, fuel pressure takes a long time (10+ seconds) to drop back to -0-psi. The fuel pressure may drop down in 'steps'. These symptoms indicate an internal injection pump problem. If the engine starts better with the lift pump disconnected, replace the injection pump. Another way to check for a faulty injection pump is to use the essential tool #3163834. The tool connects to the fuel injection pump module and isolates the problem to either the pump or to the ECM and wiring harness. Connect the tool's battery clamps to the negative and positive terminals on the battery. If the vehicle still will not start with the tool connected, you will need to replace the fuel injection pump. If the engine does start, the injection pump can be checked further by using the idle button to change between low and high idle speeds. If the engine does not respond, replace the injection pump. If the engine starts and changes idle appropriately with the tool connected, the injection pump is probably okay. IF THE CONCERN IS A HARD START/LONG CRANK TIME AFTER A 10 - 60 MINUTE HOT SOAK, there are NO CODES and fuel supply pressure is good, problem is probably a defective injection pump. A way to confirm this is to duplicate the hard start condition, then (with the engine not running) cool the injection pump with a large quantity of water (e.g. use a garden hose). If the engine start better after cooling the injection pump, the pump needs to be replaced.

 

Those were my symptoms when my CKP went out. It would always run in the morning but only crank sometime later in the day. No codes, just not getting fuel to injectors. Lift pump kicked to 15# as normal. Being stuck on the road was frustrating because I couldn't find what to change & didn't want to throw parts without an accurate diagnosis.

Deal with the codes you have. If that doesn't fix it, change the CKP. Just set the starter on the frame. No need to disconnect it. (Disconnect the batteries.) I went with lifetime aftermarket CKP because relatively new OEM part crapped out.