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I have a 94 4x4 manual transmission 22re hilux. It has 280K miles on it. It will start normally and runs well until the truck gets warm. Then is starts to lope. randomly the check engine light will come on and the engine will sputter for a few seconds and stall. It will not start again for an hour or two. Then it starts just fine and runs with no issue. I have had a few instances when I was driving, the check engine light came on and I shifted to a lower gear. If I run it at high RPM in a lower gear then I can hear the sputtering but the momentum seems to get the engine through the issue enough that I can get home where it will do its stalling. I replaced the O2 sensor several months ago and it improved but now is back to its peculiar ways. I tried checking for vacuum leaks and cannot find any. applying the brake does not seem to change anything. I only use this as a farm truck and the loping I can live with but the randomly getting stranded for 2 hrs is getting annoying. generally when it stalls I dont have a jumper wire to get the code for the check engine light and when I come back to start it in an hour or two the light is off. I have drained the gas tank and replaced with new fuel. When the stalling occurs I swear it smells like bad/old fuel from the exhaust. Any thoughts?
 

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'84 2WD Pickup
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. . . has 280K miles on it. It will start normally and runs well until the truck gets warm. Then is starts to lope. randomly the check engine light will come on and the engine will sputter for a few seconds and stall. It will not start again for an hour or two. Then it starts just fine and runs with no issue. . . .
I had this exact symptom on my truck. In my case, the problem was a failed wire in the "signal generator", the pulse pickup coil in the distributor. But other parts could cause the same trouble. Especially the spark coil. The problem has to do with a broken wire and thermal expansion/contraction causing the connection to make and break.

To track it down, I hooked up an oscilloscope (you could probably do it with a DMM too) and idled the truck in the driveway until it failed. It was quickly obvious that the output from the pulse generator went away when the engine died. On closer inspection, I could tell from the way the wire bent that the copper inside the insulation was broken.
 

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Thanks for the info. I will look at that. I hope I can find an obvious problem. I had another truck of this same year and was having similar issues. The shop I took it to replaced multiple parts including the ecm and ingniter. I ended up 800 in the hole and truck that did not run.
 

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Thanks for the info. I will look at that. I hope I can find an obvious problem. I had another truck of this same year and was having similar issues. The shop I took it to replaced multiple parts including the ecm and ingniter. I ended up 800 in the hole and truck that did not run.
It might help if you can get some baseline voltage measurements when the truck is ok. For example, ground the coil so the engine won't run and measure the voltage at the signal generator, at the igniter and at the coil while cranking. Then when it's in failure mode, check the same points and compare.
 
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