Engine stalls when warm

Hey, I have a 1997 Tacoma 2.4 The timing chain went at 440,000, so I replaced the engine.
Even though my truck is standard 2 wheel drive, my son found an automatic 4 wheel drive engine and we put it in.
It ran great for 300 miles then shut down while driving at 55 mph.
The engine will run once it cools down, but when it gets warm, it sputters and dies. (idles at 1k when cool, then when warm drops to 500, shoots back up to 1k, then back to 500 and then dies.) If I keep the rpms around 2k it runs fine until I let it down to 1k and then it just dies. It has new plugs, wires, a new coil, rotor, cap and starter. Someone told me it could be the distributor. Any ideas?

 

The first thing i'd check would be the idle control valve. It may be dirty.

 

How does the engine run in general?

When it stops and then cools down, does it run as well as it did after first being started?

 

Temp related problems point to a faulty coolant or intake air temp sensor. It's sends a cold reading to the computer even when hot. It usually won't set a code.

 

ok, now i am not getting spark from the plugs. checked the pick up coil, rotor, cap, prim and secondary coil, fuses and power to the coil is good. havent checked the air gap or the igt signal from the ecu because i don't know how to do that. anyone know how?

 

dont have a tester with me, so i really dont know. i have been looking for info on how to test the igniter. i understand that to be next in line to check.

 

I don't think there is an igniter is there ? Did they start again ?

I had them on my old toyotas pre -1st gen

 

yes there is. its mounter to the passenger side fender well behind the air intake box.

 

Then yeah that'd be a great place to check, those igniters on the old toys (Like I said, didn't even know they still used them haha)

were always suspect & almost always the first thing to check w/voltage drop/hard starting/ no spark etc;

 

ok, the igniter is good but still no spark any one know how to check the ecm?

 

Have you checked the crank sensor yet?

 

Crankshaft position sensor is within specs.

Anyone know how to check for IGTcoming from the engine control module?

 

the only thing left that I know how to do is to find a replacement ecu and check that.
any other ideas? i am really lost here...