Could we revisit the sticky throttle issue?

I realize this has been brought up, I’ve read the threads but found no solution. My 99 2.7 auto does the same friggen thing occasionally. Almost like the throttle plate is wedged shut, gotta give the pedal a pop to free it up which is interesting in traffic. The throttle is clean, the cable is clean and free, the pedal mechanism is free and clean. I do have cruise but never use it. This is driving me nuts, some one suggested the cab has become insufficiently grounded and the truck is grounding itself through the throttle cable, I suppose that could be but seems to me like it would be a more frequent problem. This happens every other day or so and I really hope someone with the same problem, who corrected it could share some insight. Thank you

 

@gearcruncher
@mechanicjon
@Bebop

 

What part of the country you in? I had my throttle freeze shut on my 99 once.

 

It’s not temp related. Happens year round. It’s the oddest and most aggravating thing. It actually takes quite a bit of force to pop it free from idle, then it’s fine for awhile then begins again. It’s just at the throttle closed position, like as you wait for a light. You put your foot on the pedal but it doesn’t move unless you quickly pop it. driving me absolutely batsh*t

 

I should mention that the issue can not be duplicated by just grabbing and twisting the throttle. It doesn’t stick. Please help

 

Are you fly by cable or fly by wire? I know it came both ways but the cruise has a cable

 

It’s an old fashioned cable to the cruise controller, old fashioned cable from there to the throttle. Free as a bird too. I’m beginning to think I need to burn some sage.. lol

 

I don't think '99 is by wire on any Toyo. engine.

Maybe a worn bushing on some kind of roller mech.?

 

My 99 was fly by cable on the v6

 

My '00 also.

I would be really looking for a worn bushing under the dash since under the hood works so freely,

 

You would think but I have been through everything a couple times now. The best way to describe it (just for discussion purposes...) is that the plate is under too much vacuum, once it’s cracked open it returns to normal. Obviously, that ain’t the problem but just a description. Im interested in hearing more about the possible grounding issue. I will entertain any suggestions at this point

 

I don't see how grounding to a non electric activated component is the problem.

The only thing electric in there is the TPS. ANy codes?

 

I don't mean to say a TPS can't cause an issue but you specifically said it feels bound up then releases and only at off idle.

It sounds like a mechanical problem.

 

No, no... it was suggested that the throttle cable was actually providing a grounding path for the cab due to a deteriorated ground elsewhere... and was getting warm, creating resistance

 

*mechanical resistance, lol

 

Run a temp ground and see if it goes away.

You should be able to see the ground strap going to the body if you look around the back. There is always one going to the firewall.

I really don't know how this occurred to him but hey, if he;s right he's right.

If you want like solutions maybe search for 'ground problems on 2.7'

I really doubt anyone had the exact same problem as a ground can be goofy as hell in diagnosing but maybe similar and maybe in electrical forum also.

My vote is a cable fray or fulcrum bushing Seen it lots from motorcycles and going looking for grounds would not be high on list.

 

You could undo the cable off the throttle and off the pedal and see how well it slides. If it feels binding there is cable lube they sell for motorcycles that will work. If the cable is internally frayed it will need to be replaced.

 

Everyone of them I've seen break (and wasn't on the fulcrum) was right at the inside edge of the sheathing, hiding it from sight.

 

Does this only happen when at idle position (foot off gas), or any time you apply throttle in any range? The vacuum concept is interesting. Does the 2.7 have anything like the idle air control valve (IAC) on the 3.4 throttle body? My 01 3.4 had this, and I didn't not have a problem with it, but it does provide a sort of air bypass around the throttle plate. If the 2.7 is similar, maybe this passage could be blocked or malfunctioning to some degree causing too much suction against the back of the plate on the plenum side.

On 3.4, note hole in bottom before the plate




This is the back side, area at bottom.


Same side, better angle though, after cleaning.


IAC attaches here (green plastic block, with sensor wires and coolant ports).


Basically this thing (internet pic)

 

Could be.