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Pete
Pete, Auto Service Technician
Category: Toyota
Satisfied Customers: 29119
Experience:  Over 17 years diagnosing and repairing automobiles various makes and models with some training and certifications.
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Idles very slow. 186.000 4.0 v6 only 200 miles on new

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idles very slow
JA: How many miles are on the car? What size is the engine?
Customer: 186.000 4.0 v6 only 200 miles on new engine
JA: What is the model/year of your Toyota?
Customer: 2006 4 runner
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: yes new mass air flow sensor
JA: Anything else you want the mechanic to know before I connect you?
Customer: no I think that that is all

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

Is or has the check engine light come on with this fault here at all?

Let me know so we can continue,thanks Pete.

Customer: replied 7 months ago.
random miss fire

Does the engine feel like it is running rough with this issue here?

Customer: replied 7 months ago.
very rough and poor fuel milage

O.k.,the misfire is causing the low idle issue.Once this misfire is located and corrected this should correct the idle fault here.

Has anything been checked or tested to try and locate or repair this misfire at all?

Let me know so we can continue,thanks Pete.

Customer: replied 7 months ago.
new plugs 2 coil packs intake and plenum gasket I think it is a vacuum leak sprayed with brake clean 2 different time but no change

Usually if it was a vacuum leak the spraying with brake cleaner would have caused the idle to raise up or idle down or run rougher as the leak sucked in the brake cleaner.

Even though these components were replaced have you tested for spark in all cylinders?

Customer: replied 7 months ago.
no I have not this is a new remain engine with only 200 miles on it with my scan tool 3 cyls show flat line and 3 show up and down lines

Did you test the fuel injectors at all?

Are the cylinders with the flat lines spark plugs soaked or wet with fuel at all?

Customer: replied 7 months ago.
the new engine came with new fuel injectors no just black not wet

Are the other spark plugs that have the up and down lines on your scan tool black as well?

Customer: replied 7 months ago.
but not as bad as others
Customer: replied 7 months ago.
one other thing up 2 th. rpm very slugsh above that 2 th. rpm it runs perfect

This sounds like a fuel fault here or an issue with an oxygen sensor ( pre catalytic converter) sending false signals causing this issue here.If you have not had the injectors tested ( fuel pressure drop test on each injector) this needs done and if this is o.k. if this model has over 100,000 miles on the original oxygen sensors I would replace them and see if this resolves the fault here.If one of these sensors is sending a false oxygen level signal in the exhaust this can cause the engine to run poorly at certain speeds or up to a certain RPM as well as cause the spark plugs to be black and misfires.If any of the fuel injectors are dropping to much pressure compared to the rest even though they came with the engine there is a chance they were faulty already and may need replaced.

With all that has been done already I would start with checking into these here.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

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