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Pete, Technician
Category: Car
Satisfied Customers: 28248
Experience:  17 years automotive training and experience.
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idle goes up to 3000 rpm down to 700rpm up and down. replace

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idle goes up to 3000 rpm down to 700rpm up and down. replace throttle body and IAV also egr four times still does it
My name is XXXXX XXXXX I am a professional here at Just Answer. I noticed that your question was not getting a response and thought I would see if you still need help with this.

If this fault had occurred after these repairs were done the first thing I would do even though it sounds like some of this has been checked is to see if there is a vacuum leak on the engine at all.In some cases this can be a leak around the intake gaskets causing this and can be difficult to see and the best way to be sure there is no vacuum leak is to have a smoke test done where smoke is injected into the intake,any smoke leaking out would indicate a leak that needs corrected.Leaking intake gaskets can be common and cause this here.

If this has already been done/checked let me know and we can continue.

Thanks Pete
Pete and 5 other Car Specialists are ready to help you
Customer: replied 4 years ago.

been a diesel mechanic for 55 years and thought I know it all. your response is logical, thought about it but vacuum test indicates a consistent reading, no fluctuation whatsoever 12lbs at low idle to 25 when returning to low idle. however you could still be right inspite of vac gauge reading. unless you could come up with another possible answer. I will replace the gskt and get back to you, hoping you are right and me wrong. I am still in learning process with cars. thanks for your time


I am following up with you to see if you still needed help with your question you had asked.If my help didn't satisfy your question please let me know so we can continue.

Thanks Pete
Customer: replied 4 years ago.

. This is sort of a project vehicle on weekends. I have not done what you suggested and proved you are right, I will refrain from giving grades or bonuses. It appears that you are right, but I need hard evidence. I will get back with the results by week-end. July 21.
Thanks for your time and patience. By the way, my name is Bill.

Sounds good Bill,let me know what you come up with here.In some cases having smoke injected into the intake can help isolate or locate a vacuum leak as well.

Thanks Pete
Customer: replied 4 years ago.

Before I asked for help in the net, I shot ether (starting fluid) around the intake manifold and it didn't cough, I assumed it was alright along with the vacuum test. But to be absolutely sure. I will change the gskt because it could be an internal leak. At times I hear gurgling sound inside the air cleaner box when surging up and down, mostly while dropping rpm. My hot rod speed racer son stated that he heard a real loud whistling sound just before it started, full throttle no doubt. But whistling sound appears like gskt. giving out. I will start from there and keep you informed. I have other things to do, so I will appreciate your patience Pete. This will be solved, time is not critical here, thanks.

O.k.,let me know how this turns out,no hurry.

Thanks Pete
Customer: replied 4 years ago.


I did replaced intake manifold gasket, but the result is the same, I will do a smoke check next, soon as I can device a tool to do it, without taking to a shop who has it, and having to pay mega $$$ per hour. Any suggestion? Like put a gofer bomb into a container, pressurized it and hook it up into the vacuum port?

, joke. Any idea will be welcome. At this point I am seriously about dumping the whole engine and put another one in. But as a diesel engine mechanic, I cant let little engine like this defeat me. Its a learning process for me, and I guarantee it will be solved. If the smoke check you suggested don't pan out , what next?. For me, engine will come out and stripped down to a single bolt then go from there. Hopefully you are right. Thanks,


If you unplug the idle air control valve when it is acting up does the idle still fluctuate or does the idle fluctuate and the vehicle stalls out?

Let me know,thanks Pete.
Customer: replied 4 years ago.

no it does not fluctuates and stalls out eventually

Customer: replied 4 years ago.

unplugging the vacuum air control valve center top of throttle body goes into normal idle, misses on acceleration and stalls out, you are correct. Next?

One thing I don't see listed here and I should have asked this before is what year make and model is this vehicle as well as engine size?(either it isn't posted or I didn't see this info in these postings)
Customer: replied 4 years ago.

Sorry Pete, its a 1991 Acura Integra, 1.8 engine with 5 speed std. trans mission. Thanks for asking, now I hope you have better idea what we are dealing with here. A lot of changes happened after these model for a good reason

Was the idle adjusting screw ever tampered with at all,this looks to be located above the air filter inlet tubing at the top of the throttle body?
Customer: replied 4 years ago.

I did unscrew it one complete turn to see if that was the problem it did not affect it in any way. So I screwed it back, same result

It is possible this may be an issue with the computer itself controlling the engine speed or in some cases I have seen worn timing components cause issues like this causing the computer to try and compensate for being out of time.These are possibilities of what may be at fault here and should be checked into as well.
Customer: replied 4 years ago.

this vehicle had overheating problems. Water pump belt head gskt and radiator was replaced. Then wont pass smog sent it to shop they retimed the engine and passed the smog. Engine operating normally till two months later this just comes up instantly when my son was driving it. I do have another computer here if you feel that's a possibility, used one from another vehicle similar to it.

If you have another computer to try out and it is the same part number from the same vehicle with the same engine and transmission it may be worth trying out to see if this is the cause here.
Customer: replied 4 years ago.

not the same part# I don't think, this one could be from a car with automatic trans (not sure). I will get back to you later I need to go work
thanks Bill

O.k.,sounds good.Thanks Pete
Customer: replied 4 years ago.

alright, just changed the computer still the same, I took the distributor out, it was leaking oil slightly. I will change the distributor by weeks end and readjust the valves. If its still the same I will take it to a diagnostic shop for evaluation. There could be some wires loose or crossed because I had a stereo system installed recently and they even fried my alternator . check engine light stayed on after that and one of the guy who is going to school for diagnostic checked it and he said one of the speaker wire was connected to the computer.

I will get back to you on Friday, p.m. thanks Pete. But let me know if there is something else simple that can cause it .

O.k.,let me know what you come up with here or if there is anything else I can assist with here.This is definitely a difficult one here.

Thanks Pete
Customer: replied 4 years ago.

Junked the car, that solved my problem. However I have another question.

where is the location for idle fuel air mixture on the carburetor of a 1981 Datsun model 510.z20 engine with endless smog hoses attached to it?.

Unfortunately my info doesn't list a vehicle this old except for some emissions data.You might try and ask this question in the NIssan/Datsun category to see if anyone can assist with this.

HERE is the link for that category.

Thanks Pete
Customer: replied 4 years ago.

thanks for your effort, I found it below towards the front of throttle cable well hidden by a maze of vacuum hoses

Your welcome.Let us know if you need anything else here or in the future.

Thanks Pete
Customer: replied 4 years ago.

Pete I was junking the Acura Integra but I am not a quitter so tried one more shot. One simple item right under my face, that I kept going around and over it. Replaced the thermo valve under the throttle body that was stuck open and that cleared everything. It runs great.
Thanks for your help and nice knowing you.

Respectfully, Bill











Thats great to hear the problem has been resolved/located.Let us know if you need anything else in the future here.

Thanks Pete