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What if the MAF is failing?
It measures about 3.5 gr entering the engine at idle (approx 800 rpm) but the documentation says it should be 4.5 to 6.3 (from memory).
If the reading is wrong and there is actually more air entering the engine, it would show as lean leaving the engine, right?
Perhaps you could find a parts store that will let you quickly install the new MAF and test, then return it if it does not correct the problem. It takes 2 minutes to swap in a new MAF sensor and installing it for 5 minutes to test does it no harm.
...also avail from Amazon in a couple of versions (here in US)
This may seem like overkill to you, but I would go ahead and replace all your vacuum hoses. They get brittle with age and one will crack and cause a leak. You will fix that one, and the increased pressure will cause another on to crack. Your car is at the age where the hoses are all leaking, or will be leaking soon. Since you will have to do it eventually, why not do it now and see if it resolves your issue (Which I think it will)
If you buy the Lexus hoses your engine will look nice and new, but you can buy enough bulk hose to do your whole engine for less than $10
Check the plug on the side . The valve on the back side, the last thing to check after all else is the intake gaskets.
Remove the entire circled and check thoroughly.
Anything here could be suspect. The tank circled should be checked throughly even if you have to remove to do so.
Any of these too. And you need to change that $8 pcv valve. You can't say it's good the spring inside could be weak or broken. Just because the valve moves when you shake it doesn't mean it's good.
Check the plug on the side . The valve on the back side, the last thing to check after all else is the intake gaskets.
Remove the entire circled and check thoroughly.
Anything here could be suspect. The tank circled should be checked throughly even if you have to remove to do so.
And you need to change that $8 pcv valve. You can't say it's good the spring inside could be weak or broken. Just because the valve moves when you shake it doesn't mean it's good.
Thanks very much, this widens the search and I will check and re-check the hoses + additional areas.
I checked the PCV valve by blowing through from either end: from 1 side air would pass, other 1 not. Really hate renewing parts that are later found to be ok; MAF being case in point.
Some hoses seem to have been replaced recently (maybe by PO), but those are mainly the ones on top that are easily accessible.
Will report back soon.
Again many thanks all for the input.
I've been driving the car without much problems (except CEL P0171/0174) and have replaced the injectors and sparkplugs which made the idle smoother.
In a constant search to find the vacuum leak I recently sprayed starter fluid underneath the inlet manifold.
SFT almost immediately went down.
So next step will be removing the inlet manifold and replacing the gaskets (all 3 of them).
04-13-18, 08:37 PM
