idle issues getting ridiculous

[fingersix]

o.k.,,looked at all the idle threads, done the tests,, for a refresher, this car 2.2liter, runs perfect, forever, if you drive around town, put it on the highway for constant distance driving, the car develops,well more like turns on a switch for a miss, then without load on the engine it stumbles and stalls, under load it goes down the highway, my last item was the coolant temp switch for maybe a weird signal to the ecm to richen mixture,,, and a third deep creep soaking of the iac,, it also tests out properly via the Haynes manual, drove car, at 18 miles it clicked and started its shenanigans, this time I drove to a Toyata dealer,,between the time at the service writer and then going to the lot to drive the car up, it went away again,,I stressed the car will present no drivability issues unless the tech goes quite far, they took the car in,,an hour or so later, they call me back to tell me an idle control motor,(iac), I said ,"well the car is idling and it checks good, how is it bad,,?", they called in the tech, he said everything checks right but the only thing that may control idle like that would be that module, but no garauntees, I then asked him about the mileage issues and he was unaware of that, the service writer failed to explain the issue properly, now he was miffed, he kinda just shrugged and said I dont know,,"it's working fine now,,",,,they did not charge me for the visit which was nice,,,. I went home rechecked the iac, it tested properly, then I took it off for a visual, looked good, went back to the dealer for a gasket,, I found Jason, the tech and showed him for his opinion, and maybe to see if he knew how it worked, he had no clue, and said they typically dont service the item, just replace them,,,,aaauuaghhh,,typical dealer b.s.,,,
does anyone know the functioning aspect of the iac,,the "air assist tube", looks to me to be a vacuume signal to the fuel pressure regulator, but the tech said no,,??its got to do something it's plumbed to the throttle body cavity,,??, and the water bypass cavity has an adjustable looking choke spring type setup,, what does this do, it somehow limits the iac valve travel,,,any help out there would be appriciated,,
Oh, yeah, after reassembly I redrove the car,,at 11 miles it happened again, I called Toyota and seen if they wanted me driving it in while it was stumbling, if that would help diagnose,, they said their tech already diagnosed it and didn't want it back unless that part was on,, the part they checked out as ok, with a shoulder shrug,,,,;-(

[Mike Gerber]

It's best to show the year of the car in your threads along witht he current mileage and anay recent work. Generation 3 2.2's are different from generation 4's. The generation 3's used a distributor with a coil inside it. If you ahve a generation 3 I would suspect the coil. They are a known problem area on generation 3's and can cause problems when they heat up. Ohm out the coil if your car is a generation 3. Another thing that can cause problems as it heats up is the fuel pump on either generation 2.2.

Mike

[fingersix]

sorry, Mike, it is a 1996, and 80k, for the most part original, new cap/ wires,new rad, this is the real little ol lady car, found here in Florida,,I have thought about those, but the heating issue confuses me, I drove this car last Friday for 74 miles around town, friends houses anywhere I could figure to go to waste time, not a hick-up, the following saturday this car sat in my drive way for 6 hours and idled, I went out ran the air, blocked the grille to bring up temp, went up and down my block, not a hick-up, get in the car cold, jump on the highway and in 10 or so miles boom,,just like the old owners told me, they never cared cause Lillian only drove to the grocery store or hair dressers, I know these guys personally so I know their story is straight,,??
I assuming 96 is generation 3,, but my coil is on the strut tower area not in the cap,,?

[Mike Gerber]

Yes, your 96 was the last year of the generation 3. If the coil is on the strut tower, you must have a car with California spec emmisions on it. Look for a label under the hood. Either way, it can still be a coil problem. I would still try to ohm out the coil. To do this you will need a digital volt/ohmeter and the specs from any manual. If you don't have a manual you can download a Toyota factory sevice manual for free at the top of the Camry forum, over at AutomotiveForums.com. Download the generation 3 manual which is actually a 94 manual, but should be fine for the areas in question on your car. The only difference would be your car is OBD2 complaint and not the older OBD1 system mentioned in the manual, so you won't be able to retrieve codes with a piece of wire. You would need an OBD2 code reader. That shouldn't be a problem at this stage of the diagnosis, unless the check engine light is on.

Mike

[stuckTaco]

I would check your ISC (Idle Speed Controller) dirty throttle body. My car (96' Camry) did the same thing until I took the throttle body apart and cleaned it. Where the ISC bolt to there's a rotating valve and over time it get stuck with crude build up. After a thorough cleaning and reassembly, the problem went away. Over the years with automotive, I have yet to see a coil die unless it's close to a heat source like the exhaust manifold.