Rpm drops to 400 car vibrates a bit then goes to normal 700 to 800k

[Kamando]

air pipes seem ok no air leak apparent ...

my suspicion goes to iacv ....

[azeem_khan]

Dear Pakwheel members,
I am having the same issue with my corolla 2012 xli. I changed air filter, spark plugs and their coils, changed throttle body, changed MAF sensor, oxygen sensor, fuel pump and filter, fuel injectors were checked as well but still the issue is there. Someone told me that it might be an issue with generator but i had it checked as well and its showing perfect on meter.
Don't know what to do. My car start dropping rpm and goes down to 200 and then car turns off. Car has been checked by three different mechanics but no one was able to resolve the issue. I spent alot of saving to fix this issue but its still there. Any help from fellow members would be grateful.

Regards,
Azeem

[Hassan1991]

Did any mechanic hooked up an obd2 sit inside and just observe the data logs when this problem occurs?

[Xulfiqar]

Put an oldschool vacuum gauge on it and check the manifold while running,

If you see less than 22 inches mercury at idle of 800 rpm, you have an air leak,

First job is to isolate all vacuum users from the engine and check for the same fault. If the isolated engine still falters, you have a manifold issue, isolate that fault with with a smoke tester or spray some carby cleaner while the engine runs on suspect joints.

Its not too complex. Get your car to an educated mechanic, not cheater ustaad maarka shaagird owning less than 20 tools.

[syedfaizan1]

clean manifold..

[azeem_khan]

Thanks a lot everyone for your suggestions. The issue was with PC valve. I have the PC Valve changed and manifold cleaned. The issue is gone ALHAMDULILLAH.

[Hassan1991]