My car shakes when the engine is on and i have my brakes pressed.?

Question

the car is fine while running. When i am stationary at a light it seems that the whole car is shaking. there are no issues while accelerating or cruising. Car shakes also when its idling.

The car is a 98 ford mustang with 75k miles on it

More details now the check engine light starts to glow :(

Answer 1

Your engine RPM is dropping to almost stall speed...that is what is causing the shaking. It is doing this because you have power brakes and the power part comes from the brake booster which is pressurized by the motor. At speed, there shouldn't be any problems. Check your vaccum lines, belts, belt tensioner, brake fluid and turn your idol up a bit. I'd say it's a good idea to change your plugs, plug wires, distributor cap/rotor and coil. While you're at it, change your fuel filter and get an oil and filter change done. Since you have 75K miles on your Mustang, it's probably about time for a transmission fluid change...or a transmission flush would be even better.

Take care of them and they'll take care of you.
Cheers!

Answer 2

A few possible problems and a simple way to determine which one it is. A vacuum leak, throttle position sensor, map sensor, or torque converter going bad. If the car runs fine in neutral or park with the brakes applied but shakes in gear your torque converter is most likely not working correctly. If it is sluggish taking gas from this point when it is shaking the throttle position sensor might be giving you problems. You can unplug it and the car should run much better if it is the problem. Don't drive it long like this because the gas mileage will be horrible. This is for test purposes only. If it is a vacuum leak bad enough to cause this problem have someone get in and hold the brakes while in gear and you open the hood and listen for a sucking sound that's out of the ordinary. If it is the brake booster you should hear it inside the car now. Lastly, Ford's number one problem with causing a car to shake your teeth loose when idling is the map sensor. The only real test is to replace it and it will cost $30 and up depending on the sensor. That's why I mentioned the other things first. You can check them for free. No, a computer won't tell you or give you a code unless the check engine light is on with the Ford. That's also about the right mileage on your car for this problem to occur. Ford map sensors are easy to replace but they tend to love hiding them. On the old T-Birds they placed them under the windshield wiper reservoir. Can you imagine how hard that sucker was to find. Your parts store can look in their books and tell you exactly were it is if they will. There are other things that can cause it but you have an 80 percent chance or better one of these, most likely the map sensor is the problem

Answer 3

ha...i love all these retards who said it needs new brakes...when you clearly said it only shakes when STATIONARY....lol. perfect example of most of the people on this site. anyway, i'd get new plugs and wires, and a new air filter. pressing the brakes takes power from the engine, and when the car is at idle or stopped in drive, this may bring engine speed down too low. not a major problem though, just do like i said.

Answer 4

Vacuum leak in or near the power brake booster.
It is creating a lean condition of one or more of the cylinders creating a miss. Take a vacumm pump and see if the boster hold vacuum. It might even be the check valve that is inline on the main Vacuum supply to the booster.

Answer 5

I think there may be a vacuum leak in your power brake booster. The leak adds more air to the engine, the engine may be drawing more fuel to keep a good mixture and that leads to brief surges in power. That's about a $90 part (remanufactured) and +/- $150 for labor.

Answer 6

If I have been you i might purchase myself a voltage meter and place it incredibly is putting for 20 volt , place the detrimental on the detrimental batter submit and the beneficial on the pos battery submit and notice what the present is.it relatively is over 12 volts, then attempt the comparable try with the motor vehicle working and notice if the present is above or around a minimum of 13.7 volts. the subject must be so straightforward as rusty or corroded battery , starter , alternator, engine block posts that must be wiped sparkling. whilst is the final time the gas filter out grow to get replaced bec it relatively is replaced as quickly as a 300 and sixty 5 days.make confident that each and one and all the belts are good and not unfastened enormously the alternator belt. The spark-plugs might must be wiped sparkling and re-gapped and wires might require their contacts to be wiped sparkling or wires replaced and ignition coil might must be wiped sparkling.additionally different plug in contacts or sensors plug in connections must be getting moister in them or require cleansing , plus the ignition coil spark plug connections must be allowing moister in and go with some anti moister jell to be utilized or they could be corroded and so on. The cruise administration situation ought to of been moister or a foul floor connection going to the cruise administration gadget or the comp. wish that enables and greater of success.via ways i wouldn't complication too plenty with regards to the minor shaking yet i might for confident examine and double examine the alternators output voltages and charging gadget connections , plus replace the gas filter out and submit to in techniques that for the period of severe temperatures and bec of moister and so on some automobiles will act up incredibly and it incredibly isn't any huge deal yet lower back issues must be wiped sparkling and checked on it.

Answer 7

basically it may need a major tune up,,this consist of plugs wires ,,a cap and button,,and the timing set on it,,also a new air filter,,and fuel filter,,it would be a real good idea to let a good mechanic do it for you,,there is some tools you may not have to do it with,,and a good mechanic will have all of them,,i own a repair shop,,and do this all the time,,it,s not a big job,,and does not cost a fortune,,i hope this helps some,,good luck with it.

Answer 8

People try to understand they said "when stationary" so how would new brakes help? They need to look for a vacum leak at the booster or near-by.

Answer 9

Can't need a tuneup if it happens only when the brake is pressed. If there is vacuum assist (power) brakes, there is probably a leak in the brake assist diaphram or the vacuum line to it.

Answer 10

If it only happens when you apply your brakes, you have warped rotors. This happens when you are going down hill and you ride your brakes causing excessive heat to the rotors. Many times you can have your rotors "turned" or shaved back to "true". If they are warped too far. You will need new rotors. Get in the habit of :gearing down on hills and you will avoid warping.