TBI with and intermittent miss

[Bow-Tie-Boy]

It's a '91 fullsize that is my DD, for now, and my weekend warrior . I have been "chasing" this for about a month now. It doesn't seem to be getting any worse, or better. This is a list of what I am running:

350 TBI motor, internaly all stock
1 inch TBI spacer
High volume MSD fuel pump
Syphon type fuel cell, mounted in the bed
All stock ignition

I do have a fuel press. guage, and it runs at a constant 13 psi. I have replaced all the typical tune up parts ie. plugs, cap, rotor, and all filters. I have checked for any codes the computer may be throwing, but nothing. I have not changed the plug wires, but I did run my hands along the entire length of each one to see if something "reached out and touched me" I think that it is an ignition problem, but if I were sure I wouldn't have to ask for help. It will miss from idle up to about 3/4 throttle, then it runs smooth again. It's not rythmic like a fouled plug, it's more random and not nearly as often, but it's still pretty annoying and embarrassing. If there is anything important that I forgot to add, let me know. Any help or suggestion would be greatly appreciated. ty

 

[4xcrazy]

replace the wires, i "chased" an intermittent miss on my 4.3 awhile back, basically did everything but the plug wires,,,"because they still looked good"

ended up being ONE of them was arching behind the block somewhere.
Every now and then you could here it *tick*

wasn't listening close enough until i had done everything else

 

[Bow-Tie-Boy]

replace the wires, i "chased" an intermittent miss on my 4.3 awhile back, basically did everything but the plug wires,,,"because they still looked good"

ended up being ONE of them was arching behind the block somewhere.
Every now and then you could here it *tick*

wasn't listening close enough until i had done everything else

Ok, I will do that. I knew I should have, but my wife is not the " well you can go ahead and get a big block" kind of wife. thank you

 

[watson85k5]

A friend of mine had this problem on his 94 k1500. It turned out to be the aftermarket ignition module. He went to gm and got the oem part and everything has been good so far.