please help me figure this out

my 91 chevy 4x4 runs strong when hot and when cold but not in between when warming up. It bogs from about five minutesa of running to about ten min. I don't know what sensor controls this as they all show good on the diag.
port. The only one that showed is the " esc" sensor but no- one can tell me what it is. please help.
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ESC...Electronic Spark Control....which would be the knock sensor down on the pssgr side frost plug position. But this wouldn't give you those symptoms.
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wrote:

I tend to agree with this. In theory if there is a issue with its control of timing it could effect performance a lot but I do not think this is the case here. You might chek/change engine coolant sensor near thermostat housing. ----------------- TheSnoMan.com
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Yes I have changed both the knock sensor and the temp sensor by thermostat could it havve something to do with the heat riser?
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wrote:

Do you have EGR on that engine configuration? If so check to see if is is disabled during warmup like it is supposed to be. ALso it is a lean bog or rich bog (I am guessing you mean lean) ----------------- TheSnoMan.com
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my egr valve does not move very easily like it says it should in my manual. I'll try a new one. I assume it's a lean bog as it almost seems starving but it's a brand new fuel pump and sender unit. I don't know what else to change as just about every sensor on the motor is brand new and it's progressed to this symptom it didn't just happen. All I can do is keep on trying. Anyone know if the heat riser could play in this, I've got headers and it isn't excactly factory but is functional. And yes it's a new O2 sensor. Any ideas????
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if you can find out what your fuel trim is doing during this condition,if o2 sensor is low .03 volts or less and you injector dwell is high ie intergrator 135 or higher that means your engine is starving for fuel and the computer is trying to fix it/that would indicate all sensor ok, look for fuel restriction or plugged cat,
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this is the likeliest possibility so far thanks man. Now, I just put three inch true duals on the truck, with new O2 sensor, but I do have a tiny fuel leak as a result of putting new pump/ sending unit in a few months ago. Could it be a pressure problem in the fuel system ya think???
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yes it is possible, but unlikly.you would be leaving a trail behind you for it to cause a problem, those pumps can but out 75psi +do you know the area of the fuel leak? sometimes the vapor fitting at the rear of the tank gets disturbed and begins to leak,
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