Surging during warm-up then random misfire at idle.

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HotRodPC

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Isn't a TBI supposed to have 14-17 PSI? You might be right and just a hair low on the fuel pressure. :shrug:
 

Georgeb

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Isn't a TBI supposed to have 14-17 PSI? You might be right and just a hair low on the fuel pressure. :shrug:

According to the factory service manual its 9-13 psi with a pump dead head at 13-18 psi...... I have about 12-13 right now with the regulator cranked up.
 

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Georgeb

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Thanks to HotrodPC for changing my thinking on the ignition timing! Went out and set it at eight degrees advance and feel like I am driving a different truck. I am pretty sure it masked whatever is causing the poopieness of the truck but Im happy with the way its running right now. It still has a very small almost unnoticable surge but it is not consistant. Will be checking for the warm up surge that comes and goes in the morning. Still going to need to figure it out to satisfy my own OCD but I can do more of that this fall when I cant work on body stuff. I am leaning towards a skewed reading from the map sensor but I need some time to diagnose since I don't have a spare to try. I would like to figure it out before I do the engine swap since it will effect what I do for aspiration. I am inclined to ditching the TBI if I can't figure it out.
 

pwlitt

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Had similar situation with my 87, EGR valve and EGR control module replacement. I did have an EGR code and a service engine soon light come on after vehicle warmed up.
 

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