Why Won't My Car Go Over 20 Mph?


6 Answers

Yun Wan Profile
Yun Wan answered
Why a car refuses to exceed a speed of 20 mph can have a range of reasons, and depends partly on the make of the car, as well as whether it uses manual or automatic transmission.

These reasons can include anything from a simple problem with the spark plugs, such as a worn plug or two, a loose or faulty lead, etc. This sounds silly, but it is possible, experience speaks in this case.

A faulty catalytic converter may equally have the effect of restricting speed, as may problems within the transmission system.

Correctly determining the cause of this problem can only be done by someone who knows what they are doing. Recruiting a friend or family member who has experience with car maintenance will obviously be the cheapest option.

Failing this, the car will have to be taken to a garage. Professionals there have the right equipment to quickly determine the cause and resolve the problem.

It is wise to get an estimate for the repairs first. Transmission problems in particular can prove to be costly. If there is a major problem, the car owner may also consider getting several quotes for repairs, as prices often vary significantly.

Depending on the age of the car, a major and expensive problem may also raise the question whether it is actually worth going through with repairs.

Older cars do tend to develop one problem after the other once they start. This may sound strange, but it is quite logical in a weird and wonderful, or not so wonderful in this case, way.

Replacing a major part within an old engine will naturally put additional strain on older parts trying to keep up with the efficiency of the new one.

Replacing an old car may ultimately be a more sensible and cost-effective solution.
Lisa Marie Halsey Muniz Profile
I had a car that did this.  I had to replace the catalytic converter on it.  I don't think it was very expensive only like $100.00 but this was years ago, and I think it depends on your car also.  But my car did the exact same thing.  If it is not the converter then you may need a tune up and need to change your spark plugs and wires, which you may know some one who is not a mechanic that can do this for you to save you some money.  Good luck.  These are just some of my suggestions it could be anything, and you may need to take it to a mechanic. 
Anonymous Profile
Anonymous answered
After running my car for 30 minute it only goes 20 miles per hour
Anonymous Profile
Anonymous answered
I have a 1992 ford tempo. It recently started doing something weird.
Sometimes I can go start it and it will work fine for about 5 to 10 mins, after that my RPM'S go up over 3000 and when I press the gas it does't do anything or it will just spit and sputter. And it will  will only basically be rolling when it does when you let go of the brake when its in drive.

I have changed the fuel filter and the spark plugs but that makes no difference.

Someone please help!!
Clifford Morton Profile
Clifford Morton answered

If the car is throwing a code, check it out. Then address the code, it could be a Mass Flow issue, cam sensor issue, tune up issue, crank sensor, etc. Run a diagnostic test and go from there. Usually costs $100 and most mechanics will do this first anyway to save time and money.

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