Deep in the plenum there is some waxy-based [stuff] that the cleaner can destroy. If it does, it is said there is no repairing it, only replacing. I can't remember, but the plenum new OEM is something absolutely outrageous. I mean, hundreds, and hundreds, and hundreds...

well, I will be honest, we did the same thing to my brother's 99 montero, and my 97 LS. Since then I drove the LS over 60k miles with no issue. just followed directions on the can. maybe carb cleaners will destroy it, but this STP cleaner is for newer vehicles and it is labeled as an air intake and throttle body cleaner that is safe for newer vehicles and sensors. so hopefully this cleaner is safe for the "waxy stuff"???

Yeah, or maybe just being generally careful makes a difference. The sense I got from past discussions, and talking with stealer people when I used to get parts locally, is that you really needed to douche the intake for it to turn into a problem. I used carby cleaner when I did mine, just didn't blast the deep hell out of / into it.

Scotty, the way I understand the danger is this. Since the air port to the isc is at the bottom of the TB, when dufusses spray a whole can in there, they flood the ISC chamber and submerge the isc pintle and the solvent eats the insulation and shorts the isc coils. You prevented this by spraying sparingly and removing the isc. There's also a mechanical (as opposed to ecu controlled) fast idle valve in there that works like a thermostat with a wax pellet inside in addition to the isc, which passes additional startup air at cold soak startup and closes very quickly. It is made into the TB and can not be replaced. In some cases the solvent penetrates the way pellet and collapses it, leaving this FIDLE valve wide open, and you can not control the idle speed below a very high level, like a permanent huge vac leak. If it runs fine now, you didn't ruin it, but just to be safe, you might mine the boneyards for a shelf TB as a backup.

Thanks for the input, that all makes sense. I think if you run the truck for a few hours at least after the cleaning, it should clean up any residue, and always wipe the bottom port dry after cleaning. Part of me wanted to have the dealer do the cleaning, that way they have to stand behind it, but I did it, it runs great now. I would think as long as you arent constantly flooding it with cleaner, you should be good.

Since cleaning my IAC, the engine is running higher rpms at idle (1900). It also kicks up a bit while I'm driving and take my foot off the gas to slow down (as the revs drop and I slow around 1200 to 1300, the computer kicks in and takes it up to 1800 or so)

I've left it running for 15 mins in park, and the "computer" has not readjusted. Is this supposed to happen naturally (been driving for 3 days and no change).

What can I do here?

R.

I don't think it matters for the high idle problem as much but did you also clean the entry to your throttle body?

I'm sure others will chime in on the high idle issue. I don't think it's normal. <img src="/forums/images/graemlins/frown.gif" alt="" />

When you cleaned the IAC, did you also clean the throttle body innards? If so, you probably got cleaning solution either too far in the IAC port or down that tiny airflow port in the bottom and it's eroded the rubber diaphragm for engine coolant temp regulated operation. In that case, it's time to start scouting for a junkyard replacement as the throttle diaphragm is not fixable AFAIK.



Otherwise, what Ray said.

Thanks for chiming in guys.

I was very very careful with my use of the cleaner. What I did find was the contacts on the inside of the IAC were heavily coated with white debris (almost like a scale). I super gently and carefully cleaned the internal contacts, but did not test them -- I'm definitely going to order a new IAC because it looked pretty rough and I have lost confidence in the part after seeing the internals.

What I'm getting now is some surging while driving in certain rpm ranges (1100 - to 1600). My a/t light is also flashing intermittently (which I'm almost sure is a dirty switch issue which I will address tomorrow).

The high idle effect was immediate after reassembly.

R.

I'd check your ISC before replacing it... unless you want to just throw parts at your rig in hope you find the problem.

As I mentioned before I don't believe the result of a blow ISC is a high idle. It's the opposite. A low idle.