1986 D-21 4cyl. 2x4 Nissan Pick-up surging/stumbling?

1986 NISSAN TRUCK
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The truck has 196,000 miles. (I am the original owner). It starts to surge/stumble upon rapid acceleration.
Gentle acceleration seems not to be a problem. It has stalled once or twice and had difficulty restarting. Two shops have not found the problem. The last shop recommended a scattershot approach (replace the coils and igniters, replace the distributor and the electronic carburetor. As these are not inexpensive parts, I am trying to narrow down the problem area. One of the coils has a very small spark compared to the other. Could this be the issue? This problem started several months ago and has become worse over time. Any ideas?
Sep 10, 2007 at 4:23 PM
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MERLIN2021
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In my opinion it is a fuel delivery issue, gentle acceleration OK Hard accel NG! Check pump pressure Carb model should be 7-9 psi.
Sep 10, 2007 at 4:32 PM
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[quote:5572e60ad1="merlin2021"]In my opinion it is a fuel delivery issue, gentle acceleration OK Hard accel NG! Check pump pressure Carb model should be 7-9 psi.[/quote:5572e60ad1]

I should explain that the surge/stumble description may not be a good explanation. The symptom seems to be
rhythmic. In other words, during rapid acceleration the
power loss is sort "on" "off" "on" "off" in a pattern so to
speak. Very consistent. I also notice the smell of unburned gas.
Sep 10, 2007 at 5:16 PM
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