Well, about 3 weeks ago my truck started having a strange idle to it. When I start my truck in the morning the idle is good and gets me to work without any trouble. But in the afternoon when i'm on my way home cruising down the highway my truck just feels like it loses power! If I step down on the throttle the truck feels like it's shaking. Then as I pull up to a stop light or stop sign the truck has a very low idle but doesn't stall out. And as I pull away the truck takes forever to accelerate and just feels gutless. It will do this all day and the next morning it starts up fine with no problems then the troubles start back up in the afternoon. I've looked everywhere for a solution! I've read it could be a coolant temperature sensor or possibly a tps gone bad. Has anyone encountered the same issue and if so any stories of success? I want my truck to run like a champ again

 

Okay so now for the good part... So I found a parts truck that has the same exact TPS as mine and I decided I'd try to change them out to see if it made a difference. Now, instead of just a low, low idle it now has a pulsing idle that no matter how much you adjust it on the idle screw and TPS it doesn't barely help at all. And when I try to give it throttle manually on the TB it sounds like the truck is bogging. I've really dug myself a good rut. Any help would be greeeeaaatly appreciated!

 

did you set the tps correctly? if you change the tps and dont set it correctly, it causes the surging.

 

I had idle problems as well. My truck would stall when I stopped at the intersection. Adjusting the idle screw would help for awhile but wasn't a permanent solution. Setting it too high will cause the computer to "hunt" for the correct idle position especially when operating the A/C.

Took throttle body and upper plenum off. They were caked in carbon. The back of the butterfly was especially carbonized. The EGR is the cause of this as it flows through a pipe in the upper plenum directly to the back of the butterfly. Once I cleaned this up it helped the idle tremendously. Adjusting the valves also helps.

 

Okay, well the TPS has been adjust correctly although I have not done a thorough cleaning on the TB and Upper Plenum. I also replaced the coolant temperature sensor as well because I've read around that if those are going bad they can cause strange idles once the truck is at operating temperatures. I haven't checked valve clearances or specs yet...But here's the deal. Once my truck gets to about 45 mph on the highway the power drops out and the truck develops a shake but if you hold the throttle at a steady speed it SLIGHTLY smoothes out. Now the only other thing I can think of is that the pickup coil in the distributor is shot. We took it out and the metal tab in the center is completely worn even with the plastic. Is it supposed to be like this?? Other than that I'm out of ideas and I don't want to keep nickel and diming myself to death. Anyone got any other places to check?

 

I would ohm out the coil and compare to specs before you condemn the coil. OEM's coils run about $100 and don't often fail. Beware of the other manufacturers selling cheap aftermarket coils.

 

i had the same exact issue on my old 2wd yota. i never did figure out the problem....

 

I had a similar condition with my truck a while back. Although mine was at a much lower RPM than you describe, seems eerily similar. See my thread here. https://www.yotatech.com/forums/f116...lerate-234182/

Replaced the pickup coil inside the distributer and havn't had the issue since. Toward the bottom of my thread is the 'Yota part number and source I used for the OEM coil.

John