Engine trouble, Dies at idle Options

[trojanhorsepower]

All,
I have been enjoying my car but have a recurring issue.
Starts great
Runs fine for maybe 20 min
Starts to once in a while act like it turned off for just a 1/2 sec then comes back on - causing the car to lurch and the shifter to jump
After about 30 or 40 min the car dies if stopped and allowed to idle. It just drops off spools down to nothing,
It restarts if you hold the gas peddle all the way down. Sometime when it restarts it is weak, then it goes fine.
As long as the car is in gear and moving it does not die.
It will continue to do this until I get home. If I am coordinated enough I can shift into neutral, work the brake with my left foot and keep the RPMs up a bit with my left and it seems fine (no stumbling or trying to die at higher RPMs) but if I come to a light, stop and let it idle it will just idle down to nothing.
Sometimes when I get home it will idle fine until I turn it off. Other times it just dies.


Seems to pull great all through the range
Always restarts

Any ideas where to start?

Thanks

Peter

[trojanhorsepower]

OK is the theory behind the CHT sensor being bad that the sensor resistance stay too high? From what I have read, as the motor heats up the resistance goes down. So for the CHT to cause this problem when the engine is warm the resistance would need to stay high? Do I have this correct?

[emerygt350]

OK is the theory behind the CHT sensor being bad that the sensor resistance stay too high? From what I have read, as the motor heats up the resistance goes down. So for the CHT to cause this problem when the engine is warm the resistance would need to stay high? Do I have this correct?

Yes, but it doesn't have to be crazy high. I suspect a few hundred ohms higher than it should be. They didn't put the 73 only resistor in that line did they? You should get us the numbers off your ECU and mps as well.

And it may not be bad. If the connection isn't good it can accomplish the same thing...

[Olympic 914]

If the connection isn't good it can accomplish the same thing...

The ECU needs to see some resistance from the CHT. If it's too high it will just be too rich but still run. Although badly, as seems your be your case.
But if it's disconnected or a bad connection it won't run.
One way to test it would be to substitute a resistor in place of the CHT.
~ 100 ohms would mimic a hot condition. Maybe not ideal if the engine is not warm. So you would unplug the CHT and add the 100 ohm resistor between the wire leading to the CHT and a good ground point. If that solves the issue your CHT sensor is bad.