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4.0 Engine rebuild starts runs but sputter and backfires


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Hello all. I recently rebuilt my 1989 4.0. Brand new internals bored .30 and new Camshaft. Starts just fine sounds great but sputters and starts to backfire on acceleration. Then the idle drops real low. I have been checking all vacuum lines. Brand new o2 sensor I tested b4 install. New plugs wires distributor and IAC. Rechecked TPS setting is right where it should be. Also brand new injectors and fuel regulator.  I’m stumped and getting agitated. Please shed some light on what I may be missing. Also timing was spot on did it per the service manual dots lined up and correct amount of pins were counted. Thanks so much hope I can sort this out. It’s been a long build and I’m ready to get drivin. 

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So I did the distributor twice. The one I have does not have a spot for you to hold it in place just the #1 on inside. When I set it it points to the #1 plug or just prior but not fully to the #1 marked in the housing. I’ll pull it and drop a pic to help with a visual but seems like it should be right. Thanks. 

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