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Gary, ASE Certified Technician
Category: Toyota
Satisfied Customers: 1052
Experience:  Senior Technician
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2009 toyota corolla runs rough at an idle in drive and

Customer Question

2009 toyota corolla runs rough at an idle in drive and stalls at stops been geeting worse finally got code p0301 checked plug clean has sound like a exhaust leak near intake manifold area car has 148000 miles
JA: Is the rough idle intermittent or consistent?
Customer: constant worse in gear was going high and low before I cleaned throttle body the other day
JA: What is the make/model of your car?
Customer: 2009 Toyota corolla 1.8 vvt
JA: Are you fixing your Corolla yourself? What have you tried so far?
Customer: yes its my daughters car . cleaned throttle body changed plugs about 5k ago
JA: Anything else you want the mechanic to know before I connect you?
Customer: I just pulled the intake to look for cracks but saw nothing obvious
Submitted: 9 months ago.
Category: Toyota
Expert:  Gary replied 9 months ago.

Hi there,

I would swap the injector from cylinder 1 to another cylinder.

Erase the P0301, and then see if what new P03xx logs.

The injectors may need to be off-car cleaned.

I would also perform an upper cylinder clean with Sea foam etc.


Customer: replied 9 months ago.
okay will do . what about that sound coming from the intake area like a small exhaust leak or could that be coming from another area just sounds like that area? are those intakes preety reliable
Expert:  Gary replied 9 months ago.

The engines are pretty reliable in most areas.

Can you listen to this noise with a length of hose to isolate it?

It may be a reflected noise from the throttle body.


Customer: replied 9 months ago.
sorry had to go to sleep ........the noise I am describing is like a truck using a jake brake not as loud but a rumbleing sound until the rpms go up and everything smoothes out sound goes away. Thinking it may be related to the vvti oil control valve either not bleeding the oil off or not working correctly . I am at work I will check when I get home.
Expert:  Gary replied 9 months ago.

How many miles on this engine?

Have you ever run an oil flush additive prior to changing the oil?

Is it nearly due for an oil change now, and would you do one to see if the noise changes?


Expert:  Gary replied 9 months ago.

Hi again,

Do you need any further help?

I hope my advice has been of assistance to you.

Kind regards