Gen 7 Idle Problem

[bf2k]

Hi

I've a problem which I hope some of you might be able to help me with.

I bought my Celica (2003 Gen 7 140bhp Face Lift Model) in Feb this year. After a week or so I the idle was quite high, around 1500-2000 RPM with an engine light. The fault all pointed to the Mass Air Flow Sensor. I changed the MAF and the stock air intake to a cold air intake. This seemed to solve the problem for a week then the engine light came on again. This time the code was P0505, Idle Control Valve problem. It ran quite happy whilst idling at 1200 RPM for a few months. If I cleared the error it would come back. Last Thursday I decided to fix the problem as I have to sell it (getting a company car). I took the ICV & throttle body out and cleaned it using some carb cleaner. I couldn't get the ICV off the bottom of the throttle body as the screws were ceased on. It looks like someone has had a go at this before but unsuccessfully because the heads are shot at. At the same time I dropped the coolant and replaced with the Prestone Coolant from tesco's (expensive but it got good reviews). This worked for a few days but Monday afternoon the idle got really rough.

My journey to work was fine. My journey home was awful. The idle didn't drop below 2000 RPM. Under load it was fine.

This morning the car idle OK. it had moments at cold where it idled at 500 RPM then to 1200 RPM. After a short journey on the motorway it idled 500-1000 RPM. At lunch I had to keep giving it gas until the car had warmed up. If I didn't the car stalled. Once the temp needle had moved to the second notch the car idled fine. This evening on my way home the car idled at 2000 RPM. After 5 minutes on the motorway I dipped the clutch and the car bounced between 1000 to 2000 RPM. After the motorway journey the idle was spot on???

Puzzled.

I'm trying to sell (although no interest as yet). I need to sort this quickly if possible. Any help would be extremely grateful.

[bf2k]

Just a quick update.

I've been out in it tonight. It started but immediately stalled. I started and gave a little bit of gas. Once I did it idled fine (1000 RPM). I drove it for about 1 mile. The temperature was 1 notch up. I turned the engine off then tried to start it again. It started and then immediately stalled. Did this a few times. I tried starting and giving gas but it just dropped off again.

Coolant level is at Full. Fan starts & stops as expected. I'm completely baffled.

[JoeyJoe]

I know this is an older post, but I though I'd post anyway just in case.

Mine done the same, it would rev to 1500 then back down, and continue to do this on idle. Occasionally it would stall. If yours does this, the ECU doesn't know what the correct idle is as it isn't getting a correct reading somewhere, it could be the control valve but if it's idling up and down, it's able to control it so that should be fine. If the idle is sticking high or low and not changing, then the idle control valve is likely the issue.

I did just remove the mass airflow sensor from the hose leading away from the air filter box, and soak the thing in brake cleaner, specifically where you will see a thin wire. It was black before cleaning and silver after.

Not had a problem with it since.