97 gmc extremely intermittent no spark

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livinginafog

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When does it die and what's the behavior of it?
My '97 yukon 5.7 hasn't run completely right ever since I put the engine back in a few months ago. It idles sort of rough and hesitates right off idle, and sometimes it feels like it'll miss once or twice while cruising at low rpm. Some days are worse than others. It's sputtered and died while getting on the gas off idle about 5 times in the 1,000 miles I've put on it. It'll also sometimes surge when stopped in fear with the ac on. That's only on its bad days though.
I have a cam position sensor code. I think the timing isn't set right.
Just wondering if your symptoms are the same.
when it runs, it runs great...about 1 1/2 yrs. ago I put a short block in it while it was apart I upgraded the spider injectors...put it back together and it been running great. about 2 or 3 months ago it started randomly dying while driving. sometimes 2 -8 times a day, sometimes it would go days without dying. started with a fuel pump relay, then fuel pump, then all my engine sensors, distributor, and ecm. also, cleaned up all ground connections on block frame and body...throughout all this it'll start right up and still randomly die although now it runs about 15 minutes max then shuts off, but it idles great, great acceleration. now I'm replacing all the battery + and - plus the power wire going to relay center and starter and all grounds
 

livinginafog

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I agree. I'd check cables. Particularly the coil cables, crank position sensor cables, etc.
Out of curiosity, how did you confirm no spark? Manually/visually? Where?
confirmed no spark by pulling a plug wire and grounding a spare spark plug and cranking it
 
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