Gamefreakgc

After a thorough search of the forums, I've decided that my situation is quite unique since I can't find a solution. First, let me give you guys some background on what's going on:

My truck was idleing poorly and I isolated the TPS as the culprit, along with a very gunked up throttle body. Here's what I did:

I took off the TB, cleaned it really good (it shines again!)
Put on the new TPS and adjusted via the FSM specs (see https://www.yotatech.com/forums/f116...1k-ohm-258259/ for what I did)
Replaced the coolant hose that enters the TB (was damaged)
Replaced coolant with red coolant instead of green
Lubed throttle cable

For two days, I was on cloud nine! It ran incredibly well . Now my throttle sticks. As the engine gets warmer, is sticks even more. It'll stick at low RPMs around town usually when I shift to neutral at at stop and it'll hold 2000 RPM for 5 sec and then drop down to idle. The part that worries me is that when it's hot, it'll stick at 3200 RPM on the freeway when I'm trying to slow down. It also sticks when accelerating and the pedal is much firmer than it used to be.

If it only stuck at 1000 to 1500 RPM I would think it was just the cable needed adjusting (which it the exact same tension it started at). But why at over 3000 RPM when the throttle is open?

Also, I'm getting a new TPS because mine is shot already. The new coolant hose I put on didn't have a bend and fused shut because of the tight curves, which I think cooked my TPS because it got too hot . I also plan on dropping some 3 in 1 oil on the throttle valve (butterfly valve) when I put the TPS on to help smooth it out.

I did not have this issue before I started, so it must have been something I did. Any ideas? Or would greasing the throttle valve and new TPS clear it all up (I really don't want to fry ANOTHER TPS!)?

Pat8942

Replace the accelerator cable, lubing it will only make it worse.

Gamefreakgc

I'm a little lost, how is that supposed to help? In my mind, lubed cable = less friction = less resistance to throttle valve, allowing to close easier. Non-lubed = more friction = more resistance which makes the valve harder to close and could make throttle stick.

xylicon

I'm gonna say that when you lubed it, it freed up a lot of dirt/gunk in there, then the lube became sticky as a result.

Slowey23

I'm gonna agree youve probably stuffed your cable by lubing it, also if the throttle body has been cooked it might have warped the butterfly a bit causing that to be sticking aswell

Gamefreakgc

I'll be working on it tommorrow so I'll take out the cable from the housing and blast it out clean with some carb cleaner (another thread suggested it).

If my butterfly valve is warped at all, is there any hope for it? I'd rather not go and buy a new TB if I can avoid it... I'll try oiling the valve real good first.

Slowey23

Yeah give that a try, just operate the butterfly by hand at the TB when it's cold and hot, if it feels fine then it would be just your cable, you could try adding another return spring on the butterfly if all else fails, it would get you by but if you have cruise control I wouldn't use it cause it may not like the extra load

Pat8942

I replaced my cable and it works as good as new,rather than trying to fix a worn out part that will never work right again, why not just get it over with and buy a new one.

OrRunner

iTrader: (1)

I am gonna say it's your return sping tension, for your throttle. Mine 87 idd the same thing, and I had replaced the cable, turns out my cable was good, my return spring was shot from being taken on and off over the years. I took my spring to a local hardware parts store and found one identical for a $1.00, put the new one on and haven't had a single problem in 2 years.

Good luck!

Gamefreakgc

Thanks for all the help guys. I just finished putting everything back together and it's much better. Here's what I did:

I took out the throttle cable (and housing, and bracket that attaches to the firewall, there's no way to only take off the cable) and took off the throttle body. I oiled the butterfly valve real good and worked in it, then wiped off any excess oil. Then I blasted out the throttle body housing several times with carb cleaner to get all the old gunk and oil I had just put in. I inspected the cable and the thin plastic lining had a small fray near the throttle end. I trimmed down the excess plastic to make it smooth, put a little grease on it and it feels MUCH better, even better than before I worked on it. I also adjusted the tension since there was a little slack and too much play with the pedal. I put the TB back on with the new TPS and put it all back together again. Took about 3 1/2 hours.

A couple of things to note, the bolts that hold the throttle cable housing should not be over tightened... I broke the bolt in half. Once it's snug and doesn't move then stop tightening it. The thread is still on there good so it's harmless but I'll never get that back out again. Also, don't buy a knock-off TPS, the thing lasted TWO DAYS! I now have a OEM Denso TPS from Autozone and it matches perfectly with the service manual.

The spring was good, thanks for the suggestion though. It has very strong tension still, I'm guessing it was replaced at one point.