Lumpy Idle and Lack of power

[AJz]

Hey. Have a slight issue with my ST182 celica that has been bothering me for quite some time.

It has an idle problem on cold starts, or starts where it has been sitting for an hour or so and has been previous driven.

Immediately after starting the car will idle high as normal, after about a min or so the revs will drop from 1200 to about 600rpm, and bounce from 500 to 600rpm. Also while this is happening the car develops a lack of power. This is until you kick your foot to the floor and all is fixed, lol. It seems anything below about 1/2 throttle, and it feels like its starving itself. This continues for about 10 mins, and then suddenly becomes fine again.
The car also stutters and bounces if you are in to higher gear, i can see the problem is only low in the rev range.

the following things have been replaced or done in the passed couple of months.....Leads, iridium plugs, takin off dizzy and rotor (checked and cleaned any gunk out of them), K&N panel filter, taking apart the throttlebody, intake and ACIS manifold and cleaned out. replaced the coolant, and the coolant temp sensor, all to no avail. Someone has suggested that the o2 sensor could be causing this problem. I hav tested the voltage across it using the diagnositcs thingywatsit, and got 0.6 volts constantly while warm running the car at 3500rpm. the volts never changed.

i cant really thing of anything else that could be causing the problem but the o2 sensor, i hav put the car on axle stands but the sensor is a bitch to get out, so i just wanna know peoples opinions before i buy another one (new or 2nd hand) and get my mate whos a mechanic to replace it.

cheers peeps.

AJ

[ndgcpr]

injectors dirty???

Mine does the same sort of thing, not quite as bad as yours but very close. I fell mine is to do with a switch that tell the ECU when the car is hot, This switches too early and for a short temperature period my car runs like crap. or if it has been driven and left to cool for a hour or so. I have been told my injectors are in need to cleaning but haven't got around to it yet. mine will actually stall if left at idel after a few 500-700-500 revs. I just try and live with it for the short period it happens in.

[spoon]

try checking/changing air flow meter

[urantia]

i'd be checking for error codes first! (short diagnostic block E1 and TE1)
And read the flashing engine light on the dash with the ignition on. If you need more info on how to do this, search old toymods forums or details, or PM.

If you suspect the o2 sensor, unplug it and take it for a drive and see what happens. (i doubt it's your O2).

As suggested it is probably your AFM, but checking for error codes should reveal this, could be TPS, again engine error codes should reveal this.

[AJz]

car is not AFM

have checked codes, flashes a 21, which is o2 sensor, was just curious if people have had similar problems and fixes for it.

[urantia]

normally with a buggered o2 or disconnected 02 you can drive around just fine, it really just fine tunes your fuel at normal cruising.

best i can offer sorry, Is it a MAP based gen2 3sge? 5sfe?

[AJz]

yea map based gen2 3sge. cheers man, will still replace the o2 sensor and let you guys know the outcome.

[oldcorollas]

intake air leak perhaps?? use something like light oil (or even water) and run over gaskets and joins... if you hear idle change, thats your leak...

[Cressida91GLX]

Problem is air flow. most probably and the 02 sensor change are resonable recommendations and also try unplugging the battery for 10 minutes . Although if it was a 7MGE than the simple answer would have been BHG!!!

If every thing fails go for a BHG test.

[takai]

Intake air leak sound familiar. But it could be low compression on one or two cylinders.

[AJz]

oh ok, i might have a decent check over the intake system.

Can anyone explain why it does it in the first 10 mins tho and never after? its like someone flicks a switch and everything is fine and dandy again.

[takai]

Could be your ISCV which isnt being controlled properly. Or if the car still uses the wax pellet style of adjustment it could be that too. That would explain why it goes away when hot.

[Cruiser97_80]

If u find nothing wrong with the intake system do a compression test .
I had a similar problem with a 3sge celica. It had low compression on 1 cylinder which turned out to be a broken ring. I am not saying that is what is wrong with yours but it may help you diagnose your problem.

[urantia]

could be low compression on 1 or more cylinders as mentioned above, well it could be. Altho you say it idles fine on first startup, and then gets shit.

I have a 3sge that misfires and runs really rouph until it warms up and comes good again,
I buahgt the engine not long ago, it had new spark plugs, new dissy cap and leads. Seemed like the previous owner figured the misfier/rouph running was spark related.

Didn't take me long to relize that the compression was low on cylinder 1. I got an air compressor into the spark plug whole on the low compression cylinder and closed the valves and listed where air was leaking from, wasn't leaking out the exuast or the air intake so that narrowed the valves out of it, pulled the dipstick and i could hear air pissing out thru there, so most likely rings are the prob in my case (or headgasket).

So once the metal expands it must be able to regain some compression and fire the fuel mixture properly.

So a comp test would be something to check out for sure.

[takai]

^^^ That is a good point, ring clearance (and HG) close up a lot when warm. So i would be inclined to check that out as well. My GZE at one point had a small HG leak when cold, but only when cold.