Ok, I have changed the "Electronic Spark control unit", the carb, the distribuitor, exhaust (cat included) and fuel filter and I am still getting a pulsing feeling when I am driving.
I have a new fuel pump that I am planning on putting but I dont think that is the problem.
The pulsing is like a missing cylinder but at idol I dont always have the pulsing.
It almost seems like a timing issue but with the new distribuitor it should not be. the distro is OEM and the plugs and wires are not old.

This is in my 81 D150 with auto tranny.

I am puzzled!!!

Thanks,

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Superman

1981 D150
"The Khaki Machine"

is the engine shaking and vibrating like a misfire?

How is the performace of it, and have you done a compression test?

Also, far off, but are you sure that its the engine, and not the brake rotors. I mean, a warped disc and a slightly stuck caliper could cause some pulsing

Hi, welcome on the board. The lean burn ("electronic spark control") system itself is likely at fault. See this thread.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I replaced the computer last year with a new one and my brakes were done also with in the last year. I dont get any steering vibration when this happens.
I can throw it in neutral and rev the engine fine with the missing falling away.
Today I drove it about 6 miles to the store and had the pulsing/hesisation and had to kick it down to get up the hill/to speed. it almost seems like the exhaust is blocked like when the cat was clogged and ogrinal but i have good exhaust flow.
I really dont think that it is the fuel pump as i get good engine response when i rev it even durning the problem.
Still puzzled.
I thought about replacing the distribuitor with another one and doing away with the spark computer but seeing as how i just replaced both it seems like a waste of money.

_________________
Superman

1981 D150
"The Khaki Machine"

Here is a good lesson learned.
While I was out at sea I had my son change my distribuitor while school was in and he still had Auto Shop in school.
Tonight I was out looking at it trying to to become unpuzzled and checked the timing.
His buddy showed up and they were telling me that they had the timing perfect.
It turns out that they had it at perfict Top Dead Center yup you read right it was set to 0 when it should have been at 16 degrees.

She runs so much better when she is timed right.

Thanks for all of the help and information.
I am glad that it was an easy fix.

_________________
Superman

1981 D150
"The Khaki Machine"

Hey Chief thanks for serving.
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

Thank you and you are welcome.

_________________
Superman

1981 D150
"The Khaki Machine"