11 votes
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How to trigger an idle throttle position re-learn?

I know this vehicle as a Yaris; 1NZ-FE engine, and that is the vehicle I am commenting on. Toyota does not mention a specific procedure for an idle relearn in their official service information. ...
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7 votes

2005 Honda Accord 4cyl revving idle when warm

You need to check for leaks in the air intake A leaky air intake can explain hunting idle and I don't think spraying carb cleaner is always conclusive as some cracks can be really hard to see/detect. ...
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  • 39k
7 votes

My BMW 325xi smells like gas

The fact that you can smell fuel in the exhaust is a strong indication that the engine is running rich. This means that there is more fuel than required by the engine. There are many things which ...
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  • 39k
7 votes

Solstice! Car starts to run rough after hitting the gas, intermittently.

Regarding the tangent, yes, an ill-fitting dipstick can be the cause of a vacuum leak. Pulling out the dipstick is a way mechanics can figure out if the car is suffering from unmetered air/vacuum ...
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  • 39k
6 votes

Idling issues on 1995 Kawasaki ZZR600

Possible Answers We were hoping for a little feedback regarding this issue prior to attempting an answer. A few things come to mind regarding the problem description and we'll run through a few of ...
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6 votes
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Rough Low Idle and Engine Shakes, Hesitation and Lack of Power

So I finally figured out the problem. First off I had a defective O2 / Lambda sensor, which I replaced. However, this had little or no noticeable effect on the problem. The valve cover gasket was ...
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6 votes

Is it healthy to drive with a bad IAC?

This wont do any damage to your engine until you have an accident making a mistake with the pedals:) The IAC would only doing the same function that you are doing manually. I do think you have more ...
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  • 20.6k
6 votes

Startup problems: low idle RPM and stall on pressing the accelerator

Not familiar with your vehicle/engine specifically, but familiar with carbed engines in general. I would think the #1 thing to look at would be the choke. Pumping before starting a carb vehicle is ...
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  • 8,403
6 votes
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2015 Honda Mobilio - Car shakes when started

If I had to guess this sounds like a four cylinder engine, with one or even two cylinder's misfiring. Best guess is a problem with either a spark plug wires, or an ignition module. I'm looking at ...
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  • 6,479
6 votes

1996 Chevy K1500 Silverado ZZ4 5.7L - Rough Idle, Plug Damage, Overheating, EGR

I see the following possibilities: Like dlu said: wrong range of spark plugs. Perhaps you can try some colder ones. When trying this: be sure to check the spark plugs soon, a too cold spark plug ...
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6 votes
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Rough Idle & Stall While Stopped

I would check the idle air control valve, or the IAC. This might likely create the exact symptoms you describe. Determining if it's working properly is a bit of a chore for a DIY person, but this is ...
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5 votes
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Engine sputtering, not accelerating. Left for 20 mins and is now fine?

Your Golf should have two fuel pumps: one for the injectors (high pressure) and one which feeds the injector pump (low pressure). The low pressure pump would reside in the fuel tank. I'm thinking the ...
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5 votes

2001 Infiniti QX4 rough idle - leaking fuel damper vacuum port

Thanks for the great detail. Considering this is a bit of an odd issue, I'll try thinking outside the box a little. But first I would use a multimeter to test the coolant temp sensor, then o2 ...
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5 votes
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2005 Honda Accord 4cyl revving idle when warm

My suggestion is that your IAC valve is sticking. This would mean it is jutting in/out and not providing the amount of air for the computer to get the engine to settle. Since you've already cleaned it ...
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5 votes

Engine hesitates and stalls when warm

The stalling issues point toward problems with an engine control system (air, fuel, or spark), but again short of replacing the fuel pump, you have already replaced the parts most likely to cause ...
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  • 6,017
5 votes
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Rough idle + slow acceleration + engine dying after spark plug change

Probably not. Engines are pretty tough. But pull a plug before you drive anymore and check for mechanical damage. Pistons hitting plugs would not be good. Also double check your plug wires and make ...
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  • 14.3k
5 votes
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Engine's RPM drops right after start and after letting off the gas

Sounds like trouble with the idle speed control valve. On the '93 Miata, it looks like this: This little guy, when working properly, will let enough air into the engine to keep the engine alive when ...
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  • 12.1k
4 votes

Engine idles badly and loudly when I switch on the A/C

An AC compressor puts a big strain on an engine when it's engaged. This is especially the case with low horse power 4-cylinder engines. What makes matters worse are high mileage engines which are in ...
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  • 9,035
4 votes

RPM bouncing when in idle, especially when AC in switched on

The Problem can be with the engine not getting enough ventilation. Problem: In your car the ECU is programmed to raise the rpm when it detects a stall or the RPM dropping down so if there is problem ...
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4 votes
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RPM bouncing when in idle, especially when AC in switched on

The exact cause of the issue had been found to be that of a loose alternator belt. When the engine was cold, the alternator had a slack in it and if the AC load is added on the engine, the rpm ...
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4 votes
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Engine Turns Over Gets to 500rpm, Shakes, Then Loses Power After Spark Plug & Wire Change

You need to go back and look at the firing order of the spark plug wires you installed. If you get two out of place on a four cylinder engine, you now only have two good firing cylinders, and ...
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4 votes

What is an acceptable amount of up/down play in a distributor shaft?

(EDIT NOTE: I made a bad assumption about the HEI distributor, so deleted all of that nonsense. Please do the following to see if it is an issue, though.) Please check the following: Take the ...
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4 votes
Accepted

Engine run-on (dieseling) condition suddenly getting much worse

I think your idea you are having a major carbon buildup is a good theory. You can try and get rid of the carbon by doing a Seafoam treatment. You mentioned are in the process of running a bottle of ...
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4 votes

My Ignition Timing is Retarded, no seriously, it's really screwed up

Good example of PID graphing. Consider the possibility that these symptoms are caused by a mixture issue instead of timing. The STFT is adding fuel and the symptom of hesitation further suggests ...
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4 votes
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My Ignition Timing is Retarded, no seriously, it's really screwed up

You probably need a new lambda sensor. Here's why: You're right - the lambda sensor needs to reach a certain operating temperature to function properly. Until it reaches that operating temperature, ...
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  • 39k
4 votes

Is it healthy to drive with a bad IAC?

As HandyHowie said, this won't cause any damage. However, there is a better way, based on the assumption that you have a foot on the brake because you leave the car in D at the lights. If the car ...
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4 votes
Accepted

08 Silverado 5.3 rough idle and dark cold start exhaust

First of all, the 5.3l engine (could be all of the Vortec LS engines, don't know) is thirsty. It drinks a bit of oil. Be aware you could be looking at up to 2 quarts between oil changes. I don't know ...
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4 votes

Rough idle + slow acceleration + engine dying after spark plug change

Don't worry about engine damage. The main difference between these 2 spark plugs is the length, the one you used is shorter. That means 2 things: the spark was not created in the best place, meaning ...
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  • 12.1k
4 votes

1996 Chevy K1500 Silverado ZZ4 5.7L - Rough Idle, Plug Damage, Overheating, EGR

My first thought here is to tackle the problems methodically, one at a time. The one that sounds most significant to me is the plug 5 damage – from what you've said it sounds like detonation (aka ...
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  • 14.3k
4 votes

Astra MK6 - when warm, rough idle and shudders while accelerating

I don't know that particular car well, but maybe a vacuum leak? Perhaps it's at the intake manifold, and worsening as the parts warm up, expand, and mating surfaces change shape?
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