When I hit the brakes the motor stumbles - Cars & Trucks

limited info generic answer fuel delivery problem carb choke --carb may need cleaning -rebuild--replacement--filter clogging--

Most definitely. Lack of a ground strap from the engine block to the chassis will damage alternators and regulators over time. I had it happen to one of my vehicles. I went through three alternators and three batteries before I stumbled onto the solution.

It's not the coils. Clean the throttle body(inside) and the mass air flow(MAF) sensor. Use brake clean. Spray the MAF on both sides. Use a tooth brush and clean the throttle inside as far as you can. Also clean the back of the throttle plate and especially were it seats against the body. Also hit the idle air control motor(IAC) with cleaner. It will take a second or two to start up. Rev it up and spray the brake clean into the throttle. Try not to let it die. This works every time, unless there are vacuum problems. Check them next.

VW have 2 temp. sensors.one for computer and one for radiator fan
you need scanner to check the temp.also vw is very bad with vacuum hoses braking.oil deep stick is part of the vacuum system.broken deep stick tube will cost the same symptoms.

Check the help links related to this problem.Click the link below to go through its troubleshooting procedure :-----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---------
Car won't start without hitting the gas pedal? http://schematicsdiagram.blogspot.com/2011/12/car-wont-start-without-hitting-gas.html
-------Complete loss of brake pedal then all gets normal? http://repairhelpcenter.blogspot.com/2012/01/complete-loss-of-brake-pedal-then-all.html
------Car dies when gas pedal is pressed? http://schematicsdiagram.blogspot.com/2011/12/car-dies-when-gas-pedal-is-pressed.html
--------Pushing on the gas pedal, but the car slows down? Gas pedal to the floor and the car slows down?

http://technoanswers.blogspot.in/2012/02/pushing-on-gas-pedal-but-car-slows-down.html

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After replacing brake rotors and pads, brake pedal remains on floor? http://technoanswers.blogspot.in/2012/02/after-replacing-brake-rotors-and-pads.html

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accelerator pedal sensor? http://technoanswers.blogspot.in/2012/02/2009-chevy-impala-accelerator-pedal.html

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For rough idle issues and problem troubleshooting,go through the help links provided below :----- van idles rough?

http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html

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will not idle when cold?

http://technoanswers.blogspot.in/2012/02/ford-explorer-40-will-not-idle-when.html

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runs lean and idles rough?

http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.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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Low idle when cold out side?

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

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Idle Air Control (IAC) Valve Replacing?

http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.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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While stop engine idles like cylinder missing?

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

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This will help.

Thanks.

Gabriel,

The first question I have is how many miles on the Lumina? If well over 100,000 Miles I strongly suspect a clogged Catalytic Converter. Before all the routine maintenance was the vehicle running normally? Another condition could be a worn out fuel pump. These are electric pumps in the fuel tank and typically will eventually fail to supply adequate fuel pressure and volume of fuel required for normal running conditions. Have an ASE Certified Technician check the Fuel Pressure and Flow Rate to determine if it is within manufacturers specifications. I had a 1994 Pontiac Transport with 175,000+ Miles and the Fuel Pump failed. I replaced it myself and then the Catalytic Converter clogged up. Both problems caused low power and stumble conditions.

Does the Check Engine Light come on when the Ignition switch is turned on before starting the engine? If not, you obviously have a bad bulb in the Instrument Cluster. This requires carefully removing the Instrument Cluster and partial dis-assembly to replace the bulb(s). I strongly suggest replacing ALL the Bulbs in the instrument cluster because of the age of the vehicle.

Is the 3.1L engine fuel injected or carburated? If FI see a professional.

Rapid Robert

your shifting cable is weared down it will go bad .

Check the large vacuum line coming from your brake booster,In it is a one way valve that stops you from forcing air backwards into the intake.Which is what your problem sounds like.The sudden extra air pushed into the intake severely leans out the motor causing the stumble.Hope this helps?

your probably feeling a rough idle of the engine. need a tune up?

in park the engine is not loaded down, just idling at a low rpm=rough
in drive with brake on you have put some load on motor also at low rpm=rough
in drive on the road engine is at higher rpm, = smoother

generally 4 cylinder motors idle a bit rough, especially if one spark plug is not firing right or fouled or one bad spark plug wire. tune up may fix it. if it is not stumbling real bad or stalling then you can live with it.

make sure the idler motor is conected and wires are free and not stuck under the intake, and also check the pcv valve lines for proper routing, also check the line going to the vacium booster for brakes, and one of the ways to find vacium leaks is by aplying brake or carburetor cleaner to the suspected area and that will change rpm when leak found