Cant Find Evap Leak Maybe Air Idler Control?

[BALOO BELLE]

my engine light comes on after a few tanks of gas. don't have the code but says evap leak small. changed oem gas cap. cant find leak with vacuum or smoke told me basically wait til something breaks. seems to be getting worse but still where no one else notices but me cause its my car! recently had throttle body cleaned but code was happening before that. ac relay was change 2 years ago n checks out ok

symptoms

vibrates at idles in drive. give it 50 to 100 rpm of gas and smooths out.

idles around 600rpm sometimes a notch above or below but always vibrates unless I give it a little gas

sometimes idle is rough like bad gas or trash in it. but passes quick

it has noticeably chugged (one beat) on two or three occasions when driving

cruise control is jerky

not shifting as smooth

engine run on sometimes, three beats

if it sounds like a.i.c can I clean it myself, where is it, and what to clean it with? im not trying to take the throttle body apart like when you clean. it it is the senor that is adjustable on the throttle body?

[BALOO BELLE]

http://us.lexusownersclub.com/forums/topic/30723-step-by-step-instructions-for-iacvidle-air-control-valveiscthrottl/

found this. is this true and correct? is it safe to use carburetor cleaner? is that different then mass airflow cleaner?

[gooden]

Ballo Belle

Here is a quote from a auto industry leader of that field :Remember our MASS AIR FLOW METER EXPERTS are available by phone or chat if you can't find what you are looking for. 1-888-907-7225. I found this on Google when my 05 es330 was acting up, I do believe my problem is same, that code comes on every1000 or1500miles. Mine idles high on start, and after fill up only reads like 288 miles to go.Where as before it would read 320 miles to empty. Someone said I was chaseing ghosts or something to mean theres nothing wrong. I hope yours gets repaired and I think youre on the right track to get it running right.

Regards

Gooden

[lexis lexus]

It's not clear to me why you think it's the IAC. But if you're '02 is similar to my '94, then you've got to take the intake off. The IAC is screwed onto the bottom of the throttle body, and those screws are a bugger to get off, I had to do it on my bench, w/ an impact driver.

The first question is what are the codes? Get the #s (autozone will do them I believe for free if you don't have a reader) and look them up. Then if it says you have a problem w/ evap leak, then start chasing those lines, not w/ smoke but w/ wd40. Trying to change or fix things willy nilly is not the best approach. See where the computer points you and then start testing out that system, sensor, etc.

How many miles? How many miles since spark plugs replaced? How many miles since o2 sensors (or whatever they're called on the '02) replaced?

LL

[BALOO BELLE]

just trying to track down what ive been told. aic is on the throttle and part of evap sys, made sense to me!

throws the same code everytime P? small evap leak. i disconnected my battery so i have to wait for the code to get the numbers. sparks and wires have been replaced. i have never replaced o2sensors. wouldn't it give a sensor code or a exhaust code?

[lexis lexus]

Ya, if you had 02 sensor probs you'd get a code for it. I was not clear that you had a code already, as you said earlier you didn't. What tells you it's a small evap leak?

If it is, you've got to do systematic work. Replace every vacuum line in the system all the way back to the gas tank if needed, as that's the cheapest and easiest thing to do. If that doesn't work, then you have to start inspecting components of the evap system. When the car is idling rough, go over every thing w/ wd40 spray and whey you find the leakl it should even out briefly. Then replace that part.

Taking off the IAC is not an easy job, at least not on my '94. It is possible there's a leak there but not my first choice. I'd look at the pastic and rubber parts first.

LL

[BALOO BELLE]

the code says exactly.... p???? small evap system leak.. that's it. I see the mapping of the evap system on the hood. just spray wd40 where the tubing meets the fixtures while car is running and look for bubbles?

[BALOO BELLE]

I changed all hoses including a leaky fuel line to canister and ventilation hose to top of engine plus almost all small lines

once I changed all the hoses the engine light came back on with new specific codes. now that its not sucking air from the hoses it can find the actual problem.

was a generic small evap sys leak code

now

P0441 Incorrect purge flow

P0446 Vent control circuit

I looked the obd2 codes up but am unfamiliar with evap system. I could only do hoses from diagram on hood. lol does this mean a vent could be broken or stuck causing the canister to not function right? it saying circuit does it mean a switch or short.. or does this just have to be inspected

http://www.obd-codes.com/p0441

http://www.obd-codes.com/p0446

[MrScott]

I had EVAP codes for a while. I started with the first and only cheap replacement being the gas cap. Parts store, and I turn it until it has clicked several times. CEL came back on after a week. When I took it to the Lexus Only Service Center I use for my oil change.... he replaced the gas cap...again, but with a OEM cap. And that corrected the issue for a long time. In the end, I ended up changing the charcoal canister myself ( my car, it's located in front of the gas tank. ugh). Not a problem since and it's been almost 3 years. If you are one of those people (like me) who tend to round up your gas purchase and top off your tank.... DON'T. I was told that's what caused the problem in the first place.

That's my 2 cents. Spend it wisely. :)

When I was having my problems, I spoke to my brother (Mr. Badwrench, and will not touch my car). The -general- design of the EVAP system is to draw fumes from the tank to the intake rather than releasing into the atmosphere. There is a solenoid control valve near the gas tank, and another along the intake, (mine is on the air filter box). I was told by a Nissan mechanic that most dealerships do not have the diagnostic software to test the solenoids for fault, but I never took it to a Lexus dealership to see if their software could isolate and test each solenoid either. The intake solenoid on the air filter box is around $90 thru Toyota parts [190922 ? -ends in 22] because I replaced mine after accidentally breaking it.