Bad Throttle Lag

04 Tacoma, manual 5 speed, SR5, V6

Problem description

Press the accelerator pedal and truck does not accelerate or accelerates slowly. Feels like the truck is going to stall or die. Press the pedal all the way down and it starts to get power. At times it is best to just pump the throttle pedal and it will accelerate. Does not do this all the time and seems to be worse on the trip home from work, but I have had it do this in the morning. Does this when you slow down and then try to accelerate, not every time and runs good at cruise speed. Again does not do this all the time. But enough to be dangerous in traffic.

What I have checked
In the service manual I have done the Throttle Body on Vehicle Inspection, check for throttle linkage is free, inspect throttle control motor for operating sound, inspect throttle control motor resistance, position sensor resistance, pedal sensor resistance . All within range. I didn,t check the accelerator pedal position sensor using the Hand-held Tester because I don't have the tester.

I thought it was the Throttle Position Sensor but it is within range at 1.6 ohm, Range is 1.2 to 3.2 ohm, The other sensor resistances are good.


Any one seen this? What is next ? Replace throttle body assembly?

 

Clutch problem? How does your clutch pedal travel feel?

 

I was supprised to read in the service manual (link below) that I did have a throttle control motor. I can hear the motor running when you follow the service manual manual procedure. The manual has you turn on the ignition switch listen for the motor and move the throttle butterfly and listen to the motor change pitch.2001-2004 Toyota Tacoma Factory Service Manual When have I done any Maintenance?, I change the oil regularly. I changed the spark plugs 6 months ago, and cleaned the throttle body about a year ago.
Clutch is good, grabs good no slipping

 

Update
As a double check I unpluged the throttle control motor again to check the throttle control motor to check the resistance per the manual. The resistance checked out per the specification. I forgot to plug it back in and drove off in the truck, had a check engine light and it would idle and run at full throttle only. I plugged it back in and reset the computer to clear the check engine light.

The problem I am having is simular but not as bad and no check engine light. So it appears that the problem may be an intermittent problem with the throttle body. They only sell the throttle body and not the sensors. That part costs over $1000 retail and is only a dealer part. I have found it online for around 700.

I will live with the the throttle lag for a while and wait and see if i throw any codes. If it keeps getting worse I may just spend 700 but dont want to spend that kind of money when i am not sure what the problem is.

 

could it be something else besides the TB. You said all the resistances read good. What about the fuel pump or injectors. could cause it to lag if its not getting the proper amount of fuel when you hit the pedal.

 

It cold be the pump or injectors but it runs fine with the throttle at wide open. So that seems to rule out both the pump and injectors. When I get the throttle lag I can floor it and it pulls hard without any lag. It only has the lag at mid range throttle and only once or twice on a 40 mile trip. Sometimes it runs fine without any problem.

 

From what you have described my truck is doing the exact thing. I have an 01 V6 Auto. It all started when I read on here that people hose out their engine bays without any problems. Naturally I have that problem now. Im gonna try plugs cause im sure it needs em anyways and I cleaned my MAF sensor cause i had it act kind of the same way before (but it threw a code then).

 

I pulled the intake rubber between throttle body and the MAF lose just enough to spray sea foam into the throttle body with the engine running. I was careful to keep it off the MAF. And I am running sea foam in the gas tank. I am still getting some throttle lag but it seems to be better, but has not been long since I did this.

This is a lot cheaper than a $700 throttle body, and I cant prove it is the TB. But if it is the TB I think it would be a worn spot on a potentiometer probably at a spot where the engine is at about 2500 RPM, because the truck runs at 2500 a lot.

 

Sea foam in the tank for a while and dont fill up at low volume gas stations. The problem appears to be poor quality gas. And Sea Foam is great. I am putting in dirt bikes, jet ski and tractor. The ethanol in the gasoline is crap.
​

 

it has been 2 weeks or more and the truck runs great after several sea foam treatments

Glad I did not buy a throttle body

 

BRP,
Is your truck still running ok? I have a very similar problem which has been going on for quite a while. I was ok after some StaBil and some other potent Yamaha treatment then the issue returned. Then after an induction service at Toyota it went away again for a while but has now returned. I posted a thread on Toyota Nation because I was unable to find any symptoms of my problem, now I see this one today. My post was long so I'll spare you guys, I was just being very thorough. Here is the link in case anyone would like to read it:
http://www.toyotanation.com/forum/showthread.php?t=387658
If you do decide to read it please let me know your thoughts, ideas. It would be much appreciated. I am at the point of having to make the choice of installing a throttle body. Don't want to ship out all the money if I don't have a 100% guarantee on it.

 

Hikeco
The sea foam has worked so far, but I am not sure why. I read the post link, the discription is very simular to what I was seeing. I would hold off as long as I could on buying a throttle body, it is just crazy expensive and Toyota is just throwing parts at the problem.

Try sea foam it cant hurt, worked for me.

And read this link and try what the 5th poster suggests, pump the throttle 0-100 % 100 times. If the problem is the TPS this procedure will/could clean the TPS potentometer and fix the problem.
http://www.tacomaworld.com/forum/1st-gen-tacomas/168680-cant-figure-hick-up-out.html

 

BRP,
Thanks for the info, and the link. I will check out the link when I have a few xtra mins.

 

OK, I did the 100 pumps, hope that helps. Haven't had the truck problem again since toyota tested the TPS and said the throttle body was bad. I think I've gone about 150 miles so far. I will be waiting till the last minute to change it believe me.

 

it has been 3 months since I pumped the accelerator 100 times. I have not had any problem with throttle lag since, I did this. So I am saying this problem is fixed. Must have been the TPS all along.

 

Mine is doing good too, although I bought the Seaform but never have used it yet. I was waiting till it had the problem again to use it. Maybe something was loose and got better when they tested the TPS. Don't know, just hope this time it doesn't come back.

 

5 months and I am convinced that the 100 pumps on the accellerator fixed the problem.

 

wtf happened to the other pages? I know theres more than this

 

This was all of this post. There are other posts on the subject

 

my 2013 is doing this also but not alot more llike i have 2000 mi on it and its done this like 5 times ,what do y mean by pumping gas pedal 100 times?when its parked or in neutral when its running?