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6

It sounds like there is an issue with something in the vehicle after it goes from open loop (before sensors are used to run the car) to closed loop (where the vehicle starts using inputs from the O2s, MAF, and other sensors). This switch over usually occurs about two minutes from a cold start-up. I would start by cleaning the MAF with electronics cleaner ...


4

I think you need to do a throttle position sensor recalibration (reset). (NOTE: I will post several different adjustment versions. I believe the top one is what you need (for a K8 engine), but will include another four depending on your engine.) To do this for your vehicle you need to follow the steps below, depending on whether it is a stick/auto and ...


4

When the valve is 'closed', it won't completely block the airflow, otherwise, as you note, the engine would choke and stop. Therefore, even if it's stuck in the closed position, some air will still get through. This should result in a slow idle - but of course if the ECU thinks more air is getting in, it will be putting more fuel in, resulting in rough ...


4

In most electronic fuel injected vehicles, there is more air getting through than what the IAC provides. This can happen with either holes directly in the throttle plates or by having them partially open (very small percentage). This is still metered air (air the computer is aware of), but it is air getting into the system. Newer vehicles with ...


3

Most likely case is a bad throttle position sensor or a bad air sensor (some cars use mass air flow, some use manifold pressure). This is typically not something that can be seen in codes, but must be identified by comparing sensor data and graphs. Other possibilities could be a vacuum leak, but that would probably throw a code/check engine light. Of ...


3

From some information I have gotten from several Mustang forums 3.8L come in two varieties. An externally balanced and an internally balanced variety was available. Model year 2000 was change year. 1994 thru 2000 were externally balanced. 2000 1/2 and up are internally balanced. What all this means is if you use the wrong flexplate the motor will shake as ...


3

Most likely a stuck A/C VSV (Vacuum Switching Valve). It's supposed to activate to increase the idle when the A/C compressor starts. When it fails you'll have crazy low RPM idle when running the A/C. Normally the A/C VSV is pretty easy to locate for pulling out and testing. Factory repair manual will have the test procedure (normally just apply the ...


3

The throttle body at this age of vehicle has a real possibility of being 'dirty'. Take off the large hose connecting the throttle body to the air cleaner at the throttle body. If the visible throttle body parts are heavily coated with cruud, then clean the throttle plate and throttle body with a tooth brush and throttle body cleaner fluid. Operate the ...


3

The ICV (Idle Control Valve) can be cleaned once removed. But, it should *not* cause the vehicle to backfire. It sounds like you're dealing with a large vacuum leak. Here are some things that you should have a look at. After checking for any obvious vacuum leaks around the top of the motor, the Vanos & Crank Case Ventilation System should be next on ...


3

I don't know of any vehicle (as equipped from the factory) that increases the idle speed to compensate for a large draw on the battery. If the alternator starts bogging the engine down then the computer should compensate to maintain the set idle speed but not make it increase. It's easy to find out if the alternator will put out enough current at idle to ...


3

Most modern engines should increase RPM's when the load on the electrical system increases, as the Engine Management system should monitor voltage and identify it being drawn low, so increasing RPM to increase output from the alternator. Even many older engines would do this.


3

I had the same problem with my car last year, problem only occurred when idling and not while driving. This is why I immediately suspected the IAC. Removing and cleaning the IAC did the trick for me. Hope this will help you.


3

The battery shouldn't make a difference, providing the alternator is working properly. However, if you don't have a starting problem, that suggests it isn't the battery that is the root cause of the problem - more like something electrical. From the symptoms you describe, it sounds more like a fuelling issue - perhaps the fuel pump is cutting out after a ...


2

If you have done any performance mods they may be contributing to your cold idle problem. Exhaust or air intake mods may put you in a borderline lean condition. You could have a lean idle circuit. This could be an adjustment/calibration problem or a dirty carb. When you open the throttle you bypass the idle circuit and the accelerator pump richens the ...


2

I did some research and on automatic-transmission models, the most common cause of this problem seems to be a broken or dirty IAC (idle air control) valve. So the first thing I tried was removing the hose from the air intake into the IAC, and spraying Seafoam into it with the engine running. In order to get the engine to run with the hose off, I had to ...


2

In all probability it is the TPS. They have been reported to have a nasty habit of malfunctioning when the battery is jumped. Particularly in the 2000 Dodge Ram for some reason. Not sure why.


2

I suspect your alternator or your battery or both are failing. Since your car needs both fuel and spark to keep the engine running it is possible that, unless you're revving up, the fuel pump and all the other electrical components are not getting enough juice to make the grade. Test the battery and alternator. This post describes the process in great ...


2

I'd put a vacuum leak or a failed idle speed controller of some type at the top of my list of suspects. Not familiar with a Focus, but those are common problems that can cause those symptoms as a car ages.


2

I did some research and found this can be caused by a dirty throttle body. I removed the air intake piping and cleaned the butterfly valves with throttle body cleaner. All good now!


2

I'm not a mechanic and have minimal knowledge with cars, so I had it towed to a garage. The mechanic there said it was a bad fuel pump. It's a rather expensive replacement with parts running about $250, and labor costing about $250 (they have to remove the gas tank and everything)


2

Strangely, after about 1500 miles the problem went away. I'm not sure why this is, though I was told by the individual that helped me with the replacement that new pumps sometimes require a "break in" period. I haven't heard that opinion echoed anywhere else, however it seems to have been the case for me... If it changes I will update! Thanks again for ...


1

Your power steering pump has a pressure release valve/device to release excessive pressure during the pumps operation. An incorrect setting would cause your symptoms. Other then a faulty pump the rest of the system needs to be checked. Steering rack defective; hoses fitted incorrectly; hoses kinked or damaged preventing fluid flow; suspension members ...


1

This particular problem was solved by replacing the coolant temperature sensor and installing a thermostat. Apparently the coolant temp sensor was telling the engine it was -20C and so it was running extremely rich and was artificially raising the idle. After replacing that the fuel mileage got much better, but it was still running a bit high, and when I ...


1

I had the same issue. I just managed to soft it. There may be a few causes to this, but for my case, I found that the idling air intake hose connecting the lower part of the throttle body was missing the hose clamp. Due to this, during idling, additional air were being sucked in via the small gap between the hose and the throttle body. I think the guy who ...


1

You may wish to read up on gasoline ethanol phase separation. This is an unfortunate scenario where ethanol in your gasoline blend absorbs too much water from the atmosphere and separates into two layers. The bottom layer contains a water/ethanol mixture which kills the engine, the top layer contains a rich mixture of gasoline and a smaller portion of ...


1

This can some times happen after periods where the car is not driven fast or for long periods of time. Engines can build up junk that will be easily cleared after a 10 min drive on the interstate. there is also the possibility of bad fuel however this is not confirmable. I would stick with the fact that there was excess build up of junk from lots of short ...


1

I'd try squirting some WD40 into the throttle body assembly first, before considering replacing it. As Paulster2 said, sometimes the body gets gummed up or, in your case, stuck from cold - WD40 will help lubricate the body and save you some money. I've used this trick a fair bit, and usually do it once during my own mini service of oil and filter change - ...


1

This might be normal behavior. From the book Auto Fundamentals, pg. 146-147 in the section "Cold Start Aids": During cold startup on some systems, an auxiliary air regulator admits additional air into the intake manifold to increase the idle speed. The auxiliary air regulator is controlled by a thermostatic switch located in the engine water jacket. ...


1

I don't know when exactly Honda stopped programming this behavior into their cars, but I do know that what you described is a warm-up sequence that some older Hondas go through by design. First a high idle, then an alternating high and low idle (1-2 seconds/cycle), then normal low idle. I would say that the behavior you describe is normal, and not ...


1

Check your throttle linkage, make sure the throttle plate is returning to idle. Look for vacuum leaks on all the hoses. The Car is idling high because it's getting too much air



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