My engine is idling at 8000 rpm. And using too much petrol. Are these problems related?

"Could this be a throttle positioning sensor problem?" - probably not. The Throttle Position Sensor (TPS) tells the computer how hard you are stepping on the gas. It does not really control idle speed.

Your problem is more likely the Idle Air Control (IAC) valve. This is a small electric valve that the computer can open and close in small steps to set the idle RPM at the desired point (a little higher when cold, then down to normal speed when warm). The IAC valve is notorious for getting all crudded up inside. Then it sticks open too much (really fast idle speed) or sticks shut (really low speed).

You can try taking it off the engine, cleaning it with carb cleaner spray, and putting it back on. That is easy and cheap.

If cleaning does not fix it, you need to buy a replacement valve and put it on. Pretty easy to do but costs more $$$.

obviously does, more RPM needs more gas

It can be issue with IAC( idle air control valve) causing the problem.

There are many other possibilities causing these idle issues. Engine idles rough.

There are few help links with solutions to troubleshoot such idle issues.

I suggest you refer the link below and follow its troubleshooting details:------

Click the link below:-----

Ford Expedition IAC valve replacing

http://technoanswers.blogspot.com/2012/12/ford-expedition-iac-valve-replacing.html

Bad miss at idle?

http://technoanswers.blogspot.com/2012/01/bad-miss-at-idle.html

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Stumbling and stalling at idle after engine rebuild?

http://schematicsdiagram.blogspot.in/2012/03/stumbling-and-stalling-at-idle-after.html

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1999 Ford F-150 Idles rough and quits when gas pedal is pressed less?

http://technoanswers.blogspot.in/2012/01/1999-ford-f-150-idles-rough-and-quits.html

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Engine stumbles coming off idle when warm?

http://repairhelpcenter.blogspot.com/2012/01/engine-stumbles-coming-off-idle-when.html

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Erratic idle on car?

http://schematicsdiagram.blogspot.com/2011/12/erratic-idle-on-car.html

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Cold start problem and vehicle shudder around 2500 to 3500 rpms

http://repairhelpcenter.blogspot.com/2012/10/cold-start-problem-and-vehicle-shudder.html

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Low idle when cold out side?

http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html

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GMC Sonoma Stalls and idles low

http://technoanswers.blogspot.com/2012/10/gmc-sonoma-stalls-and-idles-low.html

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GMC Idle Air Control (IAC) Valve Replacing?

http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.html

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1996 Camry intermittent engine failure while idle?

http://repairhelpcenter.blogspot.com/2011/10/1996-camry-intermittent-engine-failure.html

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Engine quits at idle?

http://repairhelpcenter.blogspot.com/2011/10/engine-quits-at-idle.html

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Car overheats and Air blows hot at idle?

http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html

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High Idle Problem

http://repairhelpcenter.blogspot.com/2012/10/high-idle-problem.html

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While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

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Idle flair is noticed on car? Rough idle? car will not idle? Erratic idle speed?

http://technoanswers.blogspot.in/2012/02/idle-flair-is-noticed-on-car-rough-idle.html

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High rpm in neutral? Inconsistant high RPM in neutral?

http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html

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Vehicle stumbling at idle and shows code 54?

http://schematicsdiagram.blogspot.in/2012/03/vehicle-stumbling-at-idle-and-shows.html

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Rough idle, staling and Erratic shifting?

http://technoanswers.blogspot.in/2012/03/rough-idlestaling-and-erratic-shifting.html

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While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

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These details will help.

Thanks.

When a car is idling it is at rest.The idle setting refers to the engine revolutions or 'revs'.If the setting is increased so that the 'revs' are greater,the engine will not stall at rest.This is 'high idle'!

My quest 2004 idle below 500, start up then off, have to start couple times when the engine is cold. when i pushed the gas pedal, it smells gas.

not a good situation! could blow your engine!! take it to a qualified honda dealer, and have them run code check on it- may be 'tps'- throttle position sensor. the code read may cost more than the fix! however, 8k rpms aren't healthy for your engine- so, check and fix may be cheaper than replacing engine! could also be your fuel vapor recovery canister is 'over -loaded', but unlikely!
good luck!

check automatic idle speed motor if equipped.

looks like yor air valve is not working properly.check the water imput (could be clogged). also,did you removed your termostat? if so,put it back and solve the problem.

you can ajust the engine rpm idle from the idle screw and air flow screw on the intek housing

I've got Hyundai Lantra 1.6 year 2000. It's take time to start when it's hot. When I start my car it revs at about 2k-3k rpm. It also does it when I come to a stop. When I come to a stop it will stay at a higher rpm than that of idle speed. It drives ok when on freeway but uses more petrol. I have changed the water & petrol pump but no luck