engine stumble at 1500-2000rpm

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Jul 29, 2001 | 02:17 PM

youngster

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Joined: May 2001

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engine stumble at 1500-2000rpm

Got my new motor in and have been breaking it in gently and allowing everything to seat. But I have a stumble around 1500rpm under light acceleration or cruise. I have had the truck on a scope and the iginition tests out fine. New fuel pump with plenty of volume at return line. I am wondering if the fuel pressure is a problem. I have 49psi KOEO and 44psi KOER (idle). The problem is exacerbated when I plug in the MSD 6A. I haven't put the AFPR on yet. I was waiting until the motor was broken in when I will put in the 19lb injectors. The plugs are coming out clean and are gapped at .047. Any suggestions on eliminating the stumble?

Youngster

1990 F150 I6

Jul 29, 2001 | 03:10 PM

DrFord

More Turbo

Joined: Jun 2001

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engine stumble at 1500-2000rpm

try unplugging the vacuum hose from the EGR valve(on the intake behind the troddle body) also I am not sure about your particular setup, but the factory plugg gap is .044

Jul 29, 2001 | 08:54 PM

youngster

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Posts: 63

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engine stumble at 1500-2000rpm

Tried the EGR-no luck. I am going to plan on installing the AFPR this next weekend and dialing it in to the high end of factory spec. The plugs are at .047 for the MSD. Thanks for the suggestion
Youngster