97grand4.0

Tune issues? Don’t over look this.
This old boy posted this video, and I tried it out yesterday. He apparently has done quite a few and said ' I never seen one that didn’t have play in it'
What it does is moves where the little roller bearings ride on the throttle shaft, about 1/16 inch on both sides for a total 1/8" , and replace the 4 o ring seals. So it only gives 1/16" new surface to the bearings so I don't expect it would last as long as a new TB. But it does work great, and you can see the difference. Home Depot has the O rings for under $3. But they were out of stock so went to Harbor Freight like he said in the video. Remember there are 4 old O rings to take out. Like he said mine were brittle and not sealing. Whole thing took about 40 minutes once I had the O rings.
Definitely took the play out of the shaft, which will let the TPS read more correctly and it also wont rock around on your new O rings so no vacuum leaks. I can tell the difference .
Just remember when you're digging out the old seals there are 4 of them. Video didn't make that clear right away.

dave1123

This vacuum leak is what causes idle surge, where the idle speed changes just slightly up and down. This happens because the PCM has to relearn how much air is passing thru the IAC every time the throttle plate closes and adjust the position of it to compensate. For those of you who are familiar with carburetors, worn throttle shafts cause different idle speeds when you ease the plate closed or you snap it closed. Holly carbs were the only ones I've seen with nylon bushings on the throttle shafts to help reduce this wear. The idea of roller bearings is fascinating! I had no idea these throttle bodies used them.

My WJ with 260K miles on it has a bad case of idle surge. Now I know it's cause. I also know why Seafoam destroyed my TPS! You could more than likely do the same by pushing the bearings in and putting both o-rings on the outside, making them easier to replace the next time. There will be a next time because o-rings don't like being used as rotary seals when run dry.

Great post, 97grand4.0! 012 o-rings. Good to know.

97grand4.0

I defer to the guy in the video. As far as the O rings,... two things. First if the shaft is more stable, less wear on the O rings. Second, he says these O rings have nylon in them. Maybe,? I can say the installed ID is almost the shaft OD, very little drag. They should flatten out like the old seals.

Forgot to mention about the sizes. 012 is not the size, that’s the number harbor freight assigns to them in the kit,

They are 1/2" OD x 3/8" ID x 1/16". Home Depot was out, but sells 10 of them for $2. something. Ace had only 2 and they were $1.19 each so I passed those.

If you can disconnect your cables and grab hold of the shaft and wiggle it, it's bad.

alpine.adrenaline

Thank you for the info. HD's part number is 583970, I believe.

dave1123

McMaster-Carr has Buna-N 012 0-rings for $2.82 for a package of 100.