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Low power, stumble on acceleration

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Old 10-01-2017, 05:27 PM
1990Bronco4.9 1990Bronco4.9 is offline
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Low power, stumble on acceleration

Hi all, I'm new here, hoping for help with my 1990 full size Bronco with the 4.9 six. It's weak under acceleration. It bucks if I floor it. It'll crawl along at low rpms up anything in low range. New distributor, cap, plug wires, plugs, intake manifold, exhaust manifold (was cracked) throttle position sensor, egr valve, pcm. The thing feels like the timing is retarded. It feels just like my old slant six when I'd forget to hook up the vacuum advance hose. It runs smooth at idle and low rpm/power settings, but stumbles when I try to accelerate, and bucks violently (sometimes) when I floor it. I have a timing light. Can one of you please tell me how to find the SPOUT connector? I have read that I must disconnect it before checking the timing, and I can't find it. Thanks and best regards,
Noah
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Old 10-02-2017, 10:45 AM
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The spout plug is in the wiring harness attached to the distributor.

Sounds like the motor is running excessively lean, are you getting any codes?
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Old 10-02-2017, 03:21 PM
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This might help you locate the SPOUT connector:


Or you may have the older style in-line plug similar to this:
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