When spring hits, I'm gonna give the Metro a big shot of cleaner. It might have had a bottle or 2 in its entire life.
We have an cleaner at the shop I work at that is an excellent product. It is made by Mighty and I believe it is just called "Total Intake cleaner". It is very similar to what you built, just a pressurized can that is sprayed into the intake tube(without filter) while the car is running. This cleans all the carbon out from the intake tube to the tailpipe. I went to a meeting where all the local business's meet and Mighty was talking about stuff, and he dropped an old sparkplug into some Justice Brother's injector cleaner. It bubbles and all that good stuff for about 10 minutes. It lookd alot better. Later he put it in a sample of the total intake cleaner and it started bubbling furiously again and within minutes it was VERY clean. When spring hits, I'll be using this too. I gotta beat my record this spring
Just so I didn't confuse anyone with my picture, this system I built is only for cleaning the inside of the fuel injectors and also the intake system that comes in contact after the injectors. It replaces the vehicles standard fuel supply by removing the fuel pump fuse and screwing my pressurized container directly into the fuel rail. When the fuse is removed the car won't start, as soon as I adjust the pressure pot to 30 psi the car will start and run until the can runs out. The car is running on whatever fuel/cleaner I put into this container.
I agree that it is less convenient, but RCE is claiming a typical turnaround of 24 hours and Witchhunter is claiming 2-3 days, so 'a couple of weeks' should be at the extreme outside. But like Bob suggests, how will you know if one of your injectors is leaky or not responding properly?
Sure, these guys may be able to clean injectors in the time promised. But the BIG delay is SHIPPING. Even if you are relatively close to one of these places (I live in Sacramento, which is not HORRIBLY far from either), you can count on AT LEAST 3 days shipping EACH WAY (I don't care what UPS says). If you live in the Midwest or East Coast, it is going to take even longer.
Basically you'd have to "plan" for a week's loss of the car unless you could find a local shop with an injector cleaner/tester. On aircraft we use an ultrasonic cleaner/jewelry cleaner. Aircraft nozzles are cleaned in either acetone or Hoppes #9 gun cleaner. Hoppes works 10X better but Acetone is the one required by Lycoming to do it by the book. What I'm getting at is in my case I'd clean them myself if I had the time to remove them completely. On this truck they're buried pretty badly and it takes hours to get them out.
The time investment is clearly a problem, but consider the alternatives of having an injector that is running something like 30% lean, while the others are running 10% rich. The oxygen sensor isn't going to see much of a problem there, and your fuel economy may not even suffer from it, but your emissions will be dirty and the valves in that lean cylinder may be burning or other damage may be occurring to the piston itself. So you can't count on the fact that it runs better and fuel economy is better to be indicators of injector efficiency.
That said, I'm not advocating everybody remove their injectors every time for cleaning, but if they have never been removed and tested for flow or function, you'll never know what damage a bad injector is causing until it shows up in a more major way that may require an even longer amount of down time. I'll concede it's not on the top of the list of things to be concerned about, but these 'magic in a bottle' type cleaners promote a bit of a fantasy that everything will be ok if only people used them. Clearly, as I have experienced first hand, that is not the case.
Put me in the "Snake Oil" in the gas category, about cleaning the fuel system (including the injectors).
I personally include "FP Plus" ( http://www.lcdinc.com/products_fuel_power.php ) with just about every fill up. I first heard about that product on the "Bob Is the Oil Guy" forums, and it came highly recommended. My personal experience is that I tend to have just a little better power, and a little better FE, when I use the product. The effect isn't huge, but it is quite noticeable (to me). And while the product isn't cheap (almost $50/gal + shipping), you only use 1oz per 10gal of fuel (so it's not that hard to "cost justify the price, especially given the current gas prices).
And one of the other benefits of the product, is that it is supposed to gently clean the fuel system (including the injectors) while you drive. And while I have no personal way to judge that claim (unless I wanted to take the fuel system apart and look at it), others on the BITOG forum have reviewed those claims and seem to think they have some basis in fact. So it at least appears that my FI (my car has "throttle body injection", so I only have 1 (or was it 2?) fuel injector(s) for the entire engine) is constantly being "cleaned" by the fuel additive I am using.
The other benefits of "FP Plus" (such as its lubricating properties, and the slightly better fuel economy I get when using it), would cause it to "pay for itself" (especially with today's gas prices), even without the fuel system cleaning properties. So IMHO the fuel cleaning properties (including any cleaning it does with the injectors) is just "icing on the cake" as it were).
Hey maybe the full throttle application explains some of my experance with my xB because usually after I red line it my SG reads better mileage for the rest of the trip. In my old Geo I ran a splash of STP gas treatment in every tank along with a little marvel mystery oil and without the STP it would have a bit of a stumble and lower gas mileage. Never got a chance to try Acetone in the Geo but the xB seems to like it a lot.