The issue may have been some folks were using high powered brake cleaners. Also some makes of cars have a plastic coating on the intake bore.

Note the cleaner will be running through the engine and past the 02-A/F sensors.

CRC contact cleaner appears to use CFC while MAF uses CO2 and contains alcohol. There are also some variations such as the amounts of 2-methylpentane and other chemicals. Check out the CRC safety data sheets for MAF and contact cleaners.

Don't know if CFC has any effects on engine sensors.

 

I would only use the contact cleaner to soak the sensor in with the hose removed and plugged with finger, allowing to drain into cup or rag. As for the throat and butterfly valve, I would spray and wipe that out with the throttle Body stuff. The can warns about plastic contact on the Throttle body and intake cleaner in the fine print. It is safe for the coating though, unlike reg carb cleaner. Am I missing something here?
I understand that the stuff all evaporates pretty rapidly and doesn't leave any residue. So, if you wait a few minutes following using any one of these solvents, seems that you wouldn't have to worry about getting any inside the engine or sensors. I am picturing an engine off disbursement here. As for the propellant, CFC's should dissipate into the atmosphere and not be drawn through the engine either. Am I missing something here too?

 

 

Good point in letting the chemical evaporate.

The product maker then replacing the alcohol and CFC in the contact cleaner with something that may evaporate quicker or is already a gas.

 

Well, some good news for a change! I decided to just bite the bullet and spray the throat and the the butterfly on the 72k Camry with the CRC cleaner and yes, I also put some down into the recess. This is a[[arently a federal model as there are only two hoses. Not a whole lot of spray down into the valve, but a few shots. Put it all back together and let it sit over night. Took a little bit to crank but she fired and the idle was a bit high for awhile. I drove it normally and went on some errands that I had been putting off. Not so much as a stumble! Amen
The bore was somewhat dirty and I will check the air cleaner filter and blow out rubber hose?
Now for the high mileage Camry....I bet it's filthy

 

Success! Great job!

Rubber hose?

 

Jcountry, I believe the Toyota Camry 2.2 liter engine uses a MAP "manifold absolute pressure sensor" Instead of a Mass air flow sensor. The Corolla however does.

 

The "rubber hose" I was speaking of, is the black conduit (aprox 3-4 in dia) that directs air from the filter box into the intake. It appears to be some sort of rubber compound to me. Anyway, how would you go about cleaning it? Remove it and wash it out with water and dry it? Point being, I think it might collect more dirt than the smooth metal bore does.
And thank you Toyomoho