Engine management

[3toyo]

So I had a problem with car, it was running lean, so I replaced both 02 sensors, car is running far better,

BUUUT, whenever the car isn't on choke, or moving forward the light comes on, when I'm idling, reversing at running temperature the light comes on, I believe there might be a fueling issue, I've noticed when idling at running temperature, just before the light comes on, it sounds like it's gasping, any ideas and possibly the location of the fuel rail before I start ripping stuff off

 

2004/2005 2.4 Alphard 

 

Thanks 

Edited January 23 by 3toyo

[BigNev]

If I've read what you said correctly, it can happen at any time apart from when the engine is cold and running enriched fuelling?

And a "gasp" sound.

That sounds like a possible unmetered air leak somewhere.

Extra air getting in that isn't measured by the Mass Air Flow sensor so the fuelling isn't adjusted for it.

Could be anywhere along the air intake after the MAF - assuming it has one of course!

[3toyo]

18 minutes ago, BigNev said:

If I've read what you said correctly, it can happen at any time apart from when the engine is cold and running enriched fuelling?

And a "gasp" sound.

That sounds like a possible unmetered air leak somewhere.

Extra air getting in that isn't measured by the Mass Air Flow sensor so the fuelling isn't adjusted for it.

Could be anywhere along the air intake after the MAF - assuming it has one of course!

Sorry English isn't my strongest skill, it happens whenever the engine is at the optimal running temperature idling, doesn't happen while driving, the gasp happens when the revs drop, almost like cutting out

[BigNev]

No worries mate!

Yes, my best guess is an an air leak. Check for any loose connections on the intake system, cracked hoses, and anything else like that.

 

It's beyond my abilities, but as you said the car was running lean, do you have the kit to see the long term fuel trims? And are they still lean? Not that I know what the figures should be!

 

Possibly, if there aren't any obvious leaks, try some fuel system / injector cleaner, in case it's that side of the system.

[smurf]

The only way to know for certain what is going on is to use techstream and get some live data.

 

Did it have this problem before you replaced the O2 sensors? Did you buy quality branded O2 sensors from a reputable supplier (not ridiculously cheap but apparently branded items from eBay)?