1988 Chevy Silverado My 350 5.7L wont idol!

1988 CHEVROLET SILVERADO
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WESAYITSGOINGDOWN
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Engine Performance problem
1988 Chevy Silverado V8 Four Wheel Drive Automatic 0

Can anyone help me? I just rebuilt the engine and its back in the truck, but it just wont hold an idol. It will start, run really rough, smooth out as if the ECM is taking over but then shuts down. If you open up the trottle just before it cuts off it will run roughly for another 10 seconds or so then shut down again. The first suspect was a vacuum leak but we had no luck finding one. Now im stumped. Can anyone help me?
May 28, 2009 at 7:23 PM
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RHALL77
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is your timing correct and your firing order correct? do you have fuel injection or is it a carb? can you give me a few more details?
May 29, 2009 at 11:45 AM
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WESAYITSGOINGDOWN
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yes all that was correct. after reviewing everything in the car we found that if you moved the main wiring harness it would change the way the truck ran. We soon found that a vacuum line boot had a tear in it and the harness when moved would open the hose and cause the vacuum to leak. Weve solved the mystery because it really stumped us at first. But once we reviewed the engine it was a no brainer. Thanks for your help.
Jun 2, 2009 at 2:12 PM
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