engine lopes while idling and lack of power

1988 GMC VAN
100,000 MILES • 5.7L • V8 • AUTOMATIC
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ALFREDES
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My vehicle just recently started running rough while idling. sputters,coughs when trying to accelerate.replaced EGR valve,o2 sensor,distributor cap, rotor, spark plugs, and fuel filter. problem still continues.what could the problem be?
Jun 30, 2016 at 6:32 PM
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JACOBANDNICKOLAS
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The idle issue is usually the result of a bad idle air control valve, IAC. The IAC is responsible for maintaining a smooth idle. However, the acceleration is different. Are you sure the fuel pump pressure is within the manufacturer's specs?
Jun 30, 2016 at 7:42 PM
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JACOBANDNICKOLAS
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Other thought... have you confirmed the catalytic converters are not plugged?
Jun 30, 2016 at 7:43 PM
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ALFREDES
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still having problems replaced distributor advanced timing emptied beads out of plug in catalytic converter and swapped out fuel meter body
Jul 5, 2016 at 6:28 PM
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STRAILER
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I would do an compression test, it sounds like you may have a broken valve spring.

Here is a guide to do the compression test.

https://www.2carpros.com/articles/how-to-test-engine-compression

Let us know what you find

Best, Ken

Jul 6, 2016 at 8:26 PM
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