95 LHS no start when engine warm

I have a 1995 LHS that starts up reliably, will run smoothly and drive good for about 20 miles, and then shut off. Will not start back up until it sits for 2 or 3 hours. If I drive 10 or 15 miles and it does just fine, when I shut the key off and come back 10 or 15 minutes later it will not start until it sits for 2 or 3 hours. When I say it will not start, I mean the starter turns, but no spark or fuel.

I have replaced camshaft and crankshaft sensors with new aftermarket sensors. A friend told me that the key switch could be bad, as this can shut fuel and spark off. Dont know. I am a wits end. Can anyone help?...:banghead:

Is the Check Engine light on? Usually cam and crank sensors going bad should trigger it. Lets check the car for fault codes by doing the following.

Put the key in the ignition and turn the key to the on position then off, back to on, then off and back to on again in rapid sucession and then observe the Check Engine light.

When the light goes out it will begin to flash on and off slowly, then a longer off pause then flash again, count the on flashes and write the number down, two flashing events represent a 2 digit fault code (Ex: on-off-on-off-on-off pause = 3, on-off-on-off-on-off-on-off-on-off pause = 5 the code would be 35), keep watching the light until the flashes of the CE light stops (stays off). Then shut the key off for 1 minute and repeat the process again to make certain you have the codes correct.

Any code other than 55 (End of message code) is a valid fault code, if any codes show with this procedure post them here and then well see what they are and hopefully get to the root of the problem.

Your friend may be right on his assumption with the key switch, they do tend to have problems with them going bad (I have replaced 2 so far on 2 different vehicles) but you are saying that only the engine is shutting down and not any other power accessory that is in the same circuit as the ignition system (such as the HVAC system, Turn Signals, Gauges, Power Windows, Wipers, etc.) if that isn't happening then I would not question the key switch just yet.

So lets start with checking the fault codes and go from there.

Thank you for the response! My check engine light only came on one time, and I checked the code. The only code I have gotten besides 12 is 34 (EGR solenoid shorted or stuck open). I asked my mechanic about this when I had him check it out, and he said that the EGR valve would not cause this problem.

I had him check out he fuel pump, and he said that it was ok but that when the car stalls and he tried starting it back up it was getting no fuel or spark. He says that everthing points to the crankshaft position sensor, and he thinks that I should get one from the dealership. He says the aftermarket ones are no good. (I just recently replaced camshaft and crankshaft sensors with aftermarket ones).

Any thoughts?

I'd take his word for it, My son works at the local Dodge garage and come to think about it he said the same thing one day about aftermarket sensors not working right and replacing with stock replacement ones to get results.

It also could be your ignition control module,autozone can usually test them for free.