After replacing the main relay, I continue to have the same problem with the same symptoms. The car doesn't start (engine cranks but will not turn over due to the fuel pump not being on) when the interior of the car is warm. At night or early morning there is no problem; I can immediately tell if the car will start after inserting my key in the ignition. (you hear the humm and a click of the fuel pump) The main relay I purchased is brand new from the dealer. Any suggestions... Thanks for your help.

 

In your trunk (near the back seat), there is an access panel (see pic). Back-probe that blk/yel wire connect one end of a 12V test light to it. Connect the other end to the ground bolt.

A needle will work to back-probe. I found that the mini-clip jumper wires from radio shack work well for back-probing. The copper is thin and sturdy. Just bend the hook straight and remove the spring-loaded plastic cover.

Keep the back seat down, so you can see into the trunk. Turn the key to the II position. If the light turns on for those 2 seconds that you hear the fuel pump prime, and you do not hear the fuel pump, then the fuel pump may be the problem.

 

Thanks PAhonda for your quick response. I'm not sure if what I hear (the hum and click) when I insert my key in the ignition is the the fuel pump or the relay that is directing power to the fuel pump. Actually it's probably the relay because its coming from under the dash. What I feel is key to solving this problems is the fact that it only happens when the interior of the car is warm. If I open the doors and windows and let the interior cool off, in time it will start. As I previously stated, when I turn the key two clicks and hear the hum and click from under the dash I already know its going to start. No hum and no click = no start (most likely due to no fuel) Thanks again

 

Hmm, no click with a new main fuel relay? That test I suggested above will help you troubleshoot the problem.

Just to be certain, did you change the right relay?

See: http://www.techautorepairs.com/mainrelaydefine.html

The top shows what the MFR looks like. The location is shown for the 94 towards the bottom of the page. Your 96 will have it in the same location as the 94.