After driveing vehicle for a while,especially if its hot out,when you shut off vehicle,it will not start up again. I it happens intermitently .The engine does crank and sounds like it wants to start.I usually have to wait 1 hour till i can start it right up. Problem doesnt happen as much dureing the winter months or if its cool out. Seems like you have to let engine cool.then will start.I ve replaced fuel pump so far.Any help greatly appreciated.

 

Sorry, but we need more info.
Mileage?
Did you ever change Spark Plugs?
Have you ever changed ignition coils?
Have you ever cleaned your throttle body?
Ever clean the MAF (Mass Air Flow sensor)?
Any mods ( ie CAI and which one)?
Ever have any CEL's (Check Engine Light codes)?
Ever change the PCV Valve?

 

Has 140,000 on it.New plugs,all coils,upper and lower intake gaskets,new fuel pump,just cleaned mass air sensor,pcv valve new. I dont have any codes or check engine light,thats what puzzles me. never had a IAC installled. No Modifications to engine.Engine runs fine other than this problem.Its left my wife stranded for important meetings at work.

 

I would re-set the computer and let re-learn. Unhook the negative terminal connection from battery and depress brake pedal for a few seconds. Let it sit for 15 minutes. Re-hook the negative terminal, re-start the car and let idle for 10 minutes. While doing that you may want to clean the throttle body while negative terminal is unplugged.

 

I have cleaned throttle body and i have reset computer at work, i can go in with a laptop and theres a option to relearn, i did all of this when i installed the new plugs and coils.within the last six months.A dirty throttle body doesnt sound like it would cause what im experianceing but, at this point im willing to try anything..Thanks

 

All the work you have done since that 6 months ago requires ECU re-setting again: ie you changed fuel pump, cleaned MAF, PCV. The computer needs to be re-set again. Improper cleaning of throttle body could throw that out of whack if done while battery still hooked up. See video on this page: Rough Idling Issues |*MotorWeek
logging off: good night

 

Thanks so much for all your help.Will try again and see what happens.

 

That's the only cheap solution. I was watching NASCAR race last night. After thinking about it overnight and doing some research this morning:

I was reading carbureted engines have problem with fuel vapor when hot, not so much with fuel injection and higher fuel pressure.
Because the fuel remains inside the injectors by being under a very intense pressure, engines that are fuel injected do not experience and suffer this problem as much as others do. In this case, fuel injected engines would not become so easily moved by vapors as compared to other engines. From this fact, it can be further deduced that automobiles may have different problems in starting their engines.
Another reason of a difficulty in starting a vehicle is the coinciding of the engine's hot temperature to a hot season like the summer. In this scenario, refiners alter from a fuel blend to another. Due to the process where in hot weather causes fuel to evaporate faster, gasoline refiners sometimes alter from a higher hot blooded fuel to a lower one when summer approaches. The fuel could evaporate too much that it would create too much vapor and would eventually inflict the engine. This instance happens when refiners alter back to a higher hot blooded fuel while the engine is still exposed to high temperatures of the summer season.

For the hot start, hold the gas pedal to the floor while you turn the key to see if that does anything. If it helps then you may have a leaking fuel pressure regulator or fuel injector sending fuel into the intake on hot shut down.
This may not work with leaking fuel injectors. Your problem may be your injectors and injector seals.

This is a good answer found on-line:
In the absence of fault codes the items I would suggest you look into are those that affect the mixture of fuel/air which needs to be adjusted based upon the temperature of the engine. Those would be the intake air temp sensor and the engine coolant sensor to be sure that they are in the correct range of reading of electrical resistance at hot operating temperature (which requires an ohm-meter). Also I suggest that you check the exhaust gas recirculation valve is not 'ajar' when it is required to be closed (which is when the engine is cranked for starting as well as when you slow down to a stop, and as well when you accelerate) and that requires removing the valve and inspecting its 'action' and the absence of a buildup of crud in the valve seat proper.
Most other causes of hard starting when warm are likely to be picked up by the fault code system, but subtle errors in the coolant temp sensor reading accuracy and/or egr being 'ajar' are less likely to be noticed by the on-board diagnostic capability.