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Discussion Starter #1
Hello Guys, new to the forum here.

I just purchased a 79 Supra and drove it 1300 miles home. It made the drive fine but i did notice some rough idle issues that I am hoping to fix. When it first starts the car idles fie at around 1k rpm, but ones it begins to warm up the idle flucuate as seen the video posted below. The previous owner stated he had recently replaced the spark plugs, wires, cap and rotor. fuel pressure is around 32 PSI at idle. I plan on getting some carb cleaner and looking for vac leaks.

when driving the car at low speed its likes to begin to buck. once you get on the gas or above 3k rpms it smooths out. it also sounds like there is some afterfire happening when you let off the gas.

Looking around the engine bay it appears there is a taped up whole in the intake system as pictured below. there is also this clear box wired into the car's harness, getting power from the ignition system and hooked up near the MAF. pictures are below. Any ideas on what this thing is or how to start fixing the issues above?

Covered hole
IMG_20180506_110416541.jpg

Uncovered Hole
IMG_20180506_110424553.jpg

Weird thing
IMG_20180506_110739020_HDR.jpg

Video of idling
youtube .com/watch?v=0kkPuZs56Z0

Wont let me link directly to video due to forum rules
 

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Vacuum leaks need to be resolved for sure partly causing the erratic idle. You can carefully tighten the wire clamps on all the connections...

Ive not seen anything attached to the fuel pump over ride connector before??

Check timing?

Clean TB??
 

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Where do the red/pink wires go to that are coming from the clear box??

Check all the fusible links under the hood and fuses in the quarter panel and in the dash??
 

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Discussion Starter #4
The Red wire goes across the enginebay to the ignition assembly and just used it as a power source. i think its some ebay junk meant to "increase power and efficiency"
 

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Let me guess...you just bought this from my friend Preston in Nebraska and drove it back for your Dad as a surprise? Nice car and congrats!

You are welcome to come join our FB group for 1st Gen Supra owners at https://www.facebook.com/groups/firstgenerationsupraowners/

I second the suggestion to clear up any vacuum leaks first and don't bother with carb cleaner...it is fuel injected
 

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Discussion Starter #6
Yes that is correct! the car is great and he is in love with it. the carb cleaner was to look for vacuum leaks, but a local shop will be doing a proper test as well as the valve cover and timing chain.
 

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Once potential vacuum issues have been addressed, would also advise use of Techron fuel additive. Does wonderful job of helping keep injectors varnish free and intake valves carbon free. Has also helped in cleaning the cold start injector of my 85.
 
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