EKUSMC

93' 4x4 22re and I just got it. I have cleaned tons of throttle bodies and never had this problem. It idles high (1300) now and when I press the brake it idles up and down. I know if it idles high it will make the surges when brake is pressed. I didn't take it off just did a quick clean. I checked the vacume line to the booster and the inline diafram. All is good. Should I just turn down the idle screw or take the TB off and soak it? Idled perfect before? Oh ya and like an idiot I grabbed my brake cleaner while looking at my carb cleaner and used it?? Thanks

SoCal4Running

Vacuum leak caused by wrong TB gasket.

Badger62811

Def lower the idle. I don't know exactly where the surging is set to start but I think it's around 1000-1100. From what I hear, optimum idle is 750.

WAIT WAIT WAIT. I just read the first part of your post. I had this SAME problem... My dad sprayed friggin carb cleaner in the intake while it was turned off to clean some stuff up. Once I started it, it idled way high. Sometimes the engine just kept revving higher and higher on its own. When I revved it with the pedal, say to 3000, it stayed there and never came down. Same thing if I bumped it to 5000. Only thing that has worked for me is to turn down the idle... and spray the hell out of the (here come the technical terms) things that the throttle cables connect to on the pass side of the upper intake with WD40 to loosen them up. Fight with it. Really. Even now it does it. If I'm on the freeway for a short distance, then get back onto surface streets the idle stays high until I keep the engine revved higher for a few minutes. I'm still pissed my dad went and did that.

EKUSMC

I've cleaned my old 01 4 runner 2 or 3 times and never had a problem and have done my wifes Expedition 04' with no problem. From what I've read on here, it idleing high causes the surge when brake is applied so fix that and the surge should go away. I'll try turning the idle screw down and if that doesnt work I'll take it off and soak it, get a new tb gasket and see. Any other advice out there?

The MAN

well he didn't take off the TB, so it's whatever gasket that was there before... it's possible the gasket got damaged by the brake cleaner though, but I doubt it

however, this is what I believe instead... the IAC valve is sticking... this is what happened to mine (2TZ-FE, the little brother of the 2RZ-FE), but instead of high idle I was getting inconsistent idle speeds... many times low idle with A/C running

I pulled my TB off a couple of weeks ago (not fun in a previa) and this is what I saw:



that's 18 years of crud!

a can of mopar "air intake" (carb) cleaner I had sitting around and a couple of hours later:


what did I find? there was so much crap inside the idle valve that the shaft was sticking and it wouldn't move easily, thus the servo motor was never able to move it far enough to get the correct idle speed... since I couldn't pull the shaft out, I just sprayed the hell out of it and it moves nice and good now... just don't do what I did and take off the motor and end cap on it... there's no need and that's asking for trouble as it has a spring and stopper in it

after a new gasket and reinstalling it, it idled great at cold start and it's back to what it was supposed to be... high idle when cold it idled a little high to my liking after warmed up (I have no idea what RPM it is because there's no tach ), and there's no idle adjustment for this throttle, so I had to readjust the stopper screw as there was too much air leaking past the throttle plate (I cleaned it too well )

but because I messed with the stopper screw, the freaking TPS was a little off... I got the weird surging during coasting... so I readjusted the TPS today and took it out for a spin an hour ago... runs like new again (I did seafoam the crap out of the engine a few days ago too)!



so bottom line is, you can't be lazy with extremely dirty throttle bodies... or with engines that have a lot of miles for that matter... can't just shove a rag in and do a quick lazy wipe... you're going to have to pull the throttle body off, take off the IAC and clean EVERYTHING

just remember to check the TPS to make sure it is in spec after cleaning... after years of use, it might have worn or moved which affects how the ECU gets its readings.... also, if you never take off an IAC before, I recommend using an impact driver to remove the screws... they are VERY tight and you'll strip the heads without it! If the heads are rusty, don't chance reusing them and just order new screws from the dealer... shouldn't cost more than 5 bucks... mine were rusty and I'm glad I got new screws because one wouldn't come out and I had to drill it out! Also MAKE SURE the dashpot is correctly adjusted, or it can screw with the idle... and finally, test the brake booster to make sure it is not leaking... a bad brake booster will cause idle problems... a quick way to test this is to disconnect the brake booster (WARNING: YOU WILL LOSE POWER BRAKES) and cap off the hose... if the idle is fixed/better, then the brake booster is a likely culprit

oh yeah, this is the nightmare I had to deal with:

there's practically no room to work with, there's almost no room for a screw driver to get to the TPS screws with the throttle body installed either... and there's a million brackets and hoses all attached to the throttle... taking this off takes more than an hour! So in otherwords, working on a hilux, surf, and cruiser are so much easier!

EKUSMC

Ok wow thanks for all that. Glad urs is all done.

The MAN

good luck with yours... do the brake booster hose test then take off the throttle body and give it a good thorough cleaning