Surging at idle & on throttle 04

Hey there TW,

I am seeking your help. I am experiencing surging idle-whatever speed only been 45 mph so far with it. Recently replaced 02 sensor.

Seems like if the truck is cold I can start it up and a couple blocks later it starts to surge again. At one point in traffic it would die as I slowed below 1200 or so rpms. At that point tge idle was 400 at best. Seems to be back to 800 or so.

Thoughts? Where to look first? Search the bowels of earth for a tps? This is no cbr (sport bike) I am not winning.

 

I had something similar. Cleaned the throttle body and cleared it right up.

 

Cleaned TPS, cleaned TB, replaced front 02 sensor.

Thoughts are: new o2 sensor bad? Timing belt stretched and throwing timing, iac needs replaced?

Toyo tech said my iac is part of the throttle body and to get a new/used throttle body. He said he ordered in a iac but it didnt fit and I must have an 05 TB??

 

Will be in search of junk yard throttle body. Pretty sure that 30 year toyo machanic is crazy and it is an 04 TB. The TPS sensor would be diffefent.

 

Replaced throttle body. The new one looked much cleaner than my old one inside. But I am getting the same symptoms. Idle goes up and down at around 1.5 seconds time. Than faster as I accelerate. Cant drive it smoothly.

 

Bumpidy bumpidy. Ideas??

 

did you clean the little holes just past the throttle body? You have to remove a small metal square with screws to access. Would be easier to remove the whole throttle body to fully clean, and prevent other junk from falling into the engine.



Try cleaning the MAF as well (with MAF cleaner)... spray inside the holes, and the temp air bulb. Do what the guy in this image is doing, however I would not recommend jamming the straw up the holes, you could ruin the MAF sensor.



Maf sensor can be removed by removing two screws, unplugging, and popping it out. No need to remove air box.

 

How do you clean a tps? I would suspect that thing.

 

Also check for vacuum leaks. Cracked hoses, hissing noises, surge in idle when spraying around areas of engine bay with carb clean will help narrow down areas.

 

Any check engine light codes?

 

Cleaned the holes under the screwed in cover on top the TB, Replaced the TB with a used one, cleaned TB, cleaned MAF, cleaned TPS, replaced plugs and wires, replaced O2 sensor again to make sure it was not a bad part.

I guess I gotta pay a shop again.

 

Did this too.

 

link in my sig is the 03-04 ETCS TB. It was Toyota's first attempt for Tacoma for the electronic throttle versus the cable driven

I've had random idles for awhile but mostly OK. no surging tho.

remember the 00-02 4Runner has the same TB. IAC was removed for the 03-04 due to ETCS

 

TPS is electrical, based off resistance and position. @SalemCBR did you mean something else other than TPS? If not why/how did you clean TPS?

 

The shop said they cleaned it. I have since put in another throttle body so. No change.

When I disconnect the TPS and run it, it idles 1800 and still is rising and falling 200 or so rpms once it runs just a little. Thats a surge just short of 1 second and faster as I drive it.

I did a seafoam treatment in the PCV hose and that didnt change anything. But after that I could hear a leaking air sound in or after the high part of the surge in idle. Sounds like it is near the pcv valve. Cleaned with rag and inspected those rubber components. The valve does rattle. If I pinch that hose the leaking sound goes away until pressure builds up (i think).

 

going back to your original post. did this surging happen before the O2 sensor replace? is that the reason you changed it?

 

No, i had a code for o2 sensor. Didnt surge before.

 

what was the code, and what kind of O2 sensor did you buy?

 

spray carb cleaner around the area to try to narrow down the area of the leak. If the idle changes then you've gotten close to the area. Also, the rattle test for PCV valves is not always the best indicator. If it's very old then you should probably spend the $8 or so to replace it and the grommet that it sits in. Replace the grommet because it can get hard and brittle and no longer seal properly.

 

Following. I’m experiencing the same thing. Could it be the cataletyc converter?