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Discussion Starter · #1 ·
I just tuned our 2003 Corolla yesterday in an attempt to mitigate against the high idle that has plagued the car since we bought it 4 years ago. They car has 89K miles on it now. I cleaned the TB and IAC valve THOROUGHLY, I don't think you could clean them any better. WHile it totally improved the idle smoothness, throttle responsiveness, and power/performance, IT DID NOT FIX THE HIGH IDLE PROBLEM.

SO this is where I need all of your help. Need to know if actually replacing the IAC valve with new has fixed this problem for anyone? Or if working on another system altogether fixed the issue. Could a bad coolant temp sensor cause this problem? A bad MAF cause this?

Basically, I am looking for anyone that had this problem but fixed it successfully -- I want to pick your brain and know exactly what it was you did to fix the problem.
A

Absolutely driving me insane but I know good help is around the corner. Thanks in advance for all of your help guys.

More Info... I also replaced the PCV valve with a genuine Toyota one, the old was clogged. put in new air filter, cleaned the MAF sensor. The car has no check engine trouble codes.
 

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I would check your intake manifold gasket for vacuum leaks. This seems to be a fairly common issue on the 1zzfe engines. It also would not hurt to clean the mass air flow sensor with specialized mass air cleaner.
 

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Discussion Starter · #3 ·
I just tuned our 2003 Corolla yesterday in an attempt to mitigate against the high idle that has plagued the car since we bought it 4 years ago. They car has 89K miles on it now. I cleaned the TB and IAC valve THOROUGHLY, I don't think you could clean them any better. WHile it totally improved the idle smoothness, throttle responsiveness, and power/performance, IT DID NOT FIX THE HIGH IDLE PROBLEM.

SO this is where I need all of your help. Need to know if actually replacing the IAC valve with new has fixed this problem for anyone? Or if working on another system altogether fixed the issue. Could a bad coolant temp sensor cause this problem? A bad MAF cause this?

Basically, I am looking for anyone that had this problem but fixed it successfully -- I want to pick your brain and know exactly what it was you did to fix the problem.
A

Absolutely driving me insane but I know good help is around the corner. Thanks in advance for all of your help guys.

More Info... I also replaced the PCV valve with a genuine Toyota one, the old was clogged. put in new air filter, cleaned the MAF sensor. The car has no check engine trouble codes.
I did clean the MAF sensor thankfully (with MAF cleaner). I also did take the intake manifold off to change out the thermostat (c'mon Toyota!) and did examine the gaskets. It appeared to be unsubstantial to begin with and it did appear that there were clearly some low spots on the gasket. Recommend getting new TOYOTA gasket or aftermarket? Would adding liquid gasket to the entire thing fix the issue.

BUT THE MOST IMPORTANT QUESTION i HAVE IS THIS...

HOW MANY WERE ABLE TO FIX THEIR HIGH IDLE ISSUES BY REPLACING THE INTAKE MANIFOLD GASKET? how many fixed it simply by replacing the IAC valve?
Thanks very much in advance guys.
 

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Did you resuse the intake manifold gasket? There is a revised Toyota gasket and it is not advisable to reuse any gaskets on a vehicle. Did you "reset" the ECU by disconnecting the battery for 1 hr? Most of the problems on here are from low idle, not high idle, so not sure if you will get to many responses.

Is the 1,100 RPM when the engine is cold (startup) or hot (long drive)? Is that reading taken when in park/neutral or in drive/gear? It sounds like this is at startup based on the line you had this problem about 4 years ago when you bought it. If so, 1,100 at start up is normal, it is even higher in the dead of winter.
 

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Discussion Starter · #5 ·
Did you resuse the intake manifold gasket? There is a revised Toyota gasket and it is not advisable to reuse any gaskets on a vehicle. Did you "reset" the ECU by disconnecting the battery for 1 hr? Most of the problems on here are from low idle, not high idle, so not sure if you will get to many responses.

Is the 1,100 RPM when the engine is cold (startup) or hot (long drive)? Is that reading taken when in park/neutral or in drive/gear? It sounds like this is at startup based on the line you had this problem about 4 years ago when you bought it. If so, 1,100 at start up is normal, it is even higher in the dead of winter.
Idle at warmup on this car is 2000 RPM. Resting heart rate is 1000-1100 RPM after she is fully warmed up and in neutral. Would really like to know what the factory resting heart rate is on an auto. Have read 750 and 850, which is it if either?

On the gasket question, I did reuse the TB gasket and found no flaws with it upon inspection; it creates a perfect seal. I will spray starting fluid around the TB gasket and intake manifold gasket to see if either are giving me leaks.
 

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Idle at warmup on this car is 2000 RPM. Resting heart rate is 1000-1100 RPM after she is fully warmed up and in neutral. Would really like to know what the factory resting heart rate is on an auto. Have read 750 and 850, which is it if either?

On the gasket question, I did reuse the TB gasket and found no flaws with it upon inspection; it creates a perfect seal. I will spray starting fluid around the TB gasket and intake manifold gasket to see if either are giving me leaks.
Base idle speed is 750 +-50 RPM. Did you try the reset?
 

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Discussion Starter · #9 ·
Problem solved

WE HAVE RESOLUTION -- 100%

All it took was another day of driving for the ECU to adjust to the tune-up and service and we are now at a perfect 750 RPMs! Dead on perfect without hesitation or stumbling. Love it. My friend, the owner, will be very happy they have had high idle issues with this car since they bought it over four years ago and none of the shops have been able to bring resolution. So my combination therapy did the trick. But I am convinced it was the absolute removal and reconditioning of the IAC valve that did the trick primarily, but the TB cleaning had to have helped as well.

Thanks for everyone's help. Please point folks in this direction if they are having high-idle issues -- or just PM me.

Thanks again.
 
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