Ok so this problem has been persistent for about a month now. The car, a 92 automatic coupe with 180K miles on it, will start up cold, run fine, and then when it reaches its operating temp, it will shut off as if you turned the key off. No sputtering, loss of power or odd noises, it will just cut off instantly. This never happens at speed, only when it is slowing down (like approaching a stoplight, stop sign, turn lane). After it cuts out, The car will crank and the fuel rails will pressurize to about 45 PSI but it will not restart for another 5 minutes or so, I'm assuming after it has time to cool off. It also will run fine when it is parked at idle, it only dies on the deceleration. Last May, 8 months ago, I replaced the spark plugs, spark plug wires, opti spark, ICM, ignition coil, a bad injector that did not ohm out correctly (the others are all within their operating ranges, hot and cold), MAP sensor, Throttle position sensor, Coolant temp sensor, Air intake temp sensor, Fuel pump, fuel pressure regulator, and fuel filter. Recently however, the water pump went bad and began leaking out of the weep hole. I had to continue driving the car as I needed to use it and did not have time to get to the water pump. After the pump went, these stalling problems began. I puled codes off of the ECM and engine and only got code 12 on the engine (which means it is running fine) and C12 and H74 off of the ECM. I also replaced the ICM and Coil and made sure to use plenty of dielectric grease on the ICM. I also replaced the EGR solenoid and EGR valve on the back of the block. A shop looked at it, and could not get it to die, and said all fuel pressure readings were good, timing was fine, and the car ran great overall. Also, not going to lie, when I replaced the opti the first time, I did buy a cheap one online, I can't remember the company. Because the problem is intermittent, it's tough to diagnose it, especially because it only dies at stoplights where pulling out my voltmeter and testing resistances is kind of low on the priorities list, after moving the car out of an intersection. Anybody else having this problem or anything similar? Any suggestions, maybe I'm missing something?

 

have you checked the function of the IAC ( Idle Air Control)

 

Do you mean checked it's resistance?

 

Fuel injector pintle sticking. Usually happens hot. Will flood it out.

What decision was made to replace so many parts? You couldn't possibly found all that stuff gone bad.

You might as well just buy new injectors, IAC, ignition switch, check the wiring, etc, etc.