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Discussion Starter · #1 ·
So after getting the truck back to spec, now the throttle is surging again, i did remove the rear emissions valve and plugged it with vaccum caps, not sure if its because of that but you never know

Any help or suggestions to look into it im all ears!
Thanks
 

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yo Fox,
See my Vacuum leak test in post #11 incl jowens126 's HVAC Control Panel info @ Help with dtc codes and idle
Excerpts:
When vacuum leaks are indicated, search out and correct the condition. Excess air leaking into the system will upset the fuel mixture and cause conditions such as rough idle, missing on acceleration, or burned valves. If the leak exists in an accessory unit, such as the power brake, the unit will not function correctly. Or Air Conditioning when in MAX mode may switch to Defrost.
 

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1986 Eddie Bauer 5.0EFI AOD Full length headers Y pipe into single 3" Magnaflow 3" factory exit
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I bought a smoke machine, it didn't find anything for me. I was hoping to see a definite leak, but it didn't do shit for me....

My best method was to unplug vacuum lines at the manifold octopus one at a time, and blocking the inlet of the line you just pulled with your finger one at a time, looking for the one that fixes the surge when you plug it with your finger, esencially stopping the vacuum leak....

Its a good way to narrow down which line is leaking, from there you can find it by following along that line, and unplugging connections, blocking them with your finger, till you find the one that still surges, telling you its the line you are plugging with your finger.

I just ended up replacing ALL of my vacuum lines, they were so brittle they had cracks everywhere. You can fight it all you want, you'll just be chasing the problem all the time until you finally break down & replace all of them. They are 25 years old, they are way over due to be replaced!
 

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Discussion Starter · #5 ·
I bought a smoke machine, it didn't find anything for me. I was hoping to see a definite leak, but it didn't do shit for me....

My best method was to unplug vacuum lines at the manifold octopus one at a time, and blocking the inlet of the line you just pulled with your finger one at a time, looking for the one that fixes the surge when you plug it with your finger, esencially stopping the vacuum leak....

Its a good way to narrow down which line is leaking, from there you can find it by following along that line, and unplugging connections, blocking them with your finger, till you find the one that still surges, telling you its the line you are plugging with your finger.

I just ended up replacing ALL of my vacuum lines, they were so brittle they had cracks everywhere. You can fight it all you want, you'll just be chasing the problem all the time until you finally break down & replace all of them. They are 25 years old, they are way over due to be replaced!
this is a good method, let me give it a try
 

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1986 Eddie Bauer 5.0EFI AOD Full length headers Y pipe into single 3" Magnaflow 3" factory exit
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Till you pull the map sensor line & it immediately stalls!! Haha!!

I ended up figuring out my cruise control module was the source of my leak, i pulled that vacuum line, plugged the steel post with my finger & the idle smoothed out. Upon further inspection, it was due to the cruise control moudule being completely rusted out on the back side.
 

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Discussion Starter · #7 ·
Till you pull the map sensor line & it immediately stalls!! Haha!!

I ended up figuring out my cruise control module was the source of my leak, i pulled that vacuum line, plugged the steel post with my finger & the idle smoothed out. Upon further inspection, it was due to the cruise control moudule being completely rusted out on the back side.
ill have to check the cruise control on mine

Also could be the 2 caps i put for the emissions system where the rear valve goes, should i put them together like a by pass or is the caps ok? cause it only happened when i did that removal
so i need help
 
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