Q: At highway speeds, car loses power

asked by on October 03, 2016

At highway speeds, my car experiences loss of power. This problem is intermittent and it has been serviced “five” times; however, the problem continues. The engine is making a ticking sound and there is a power drop of about 35 mph. The dealership replaced the fuel filter, fuel gauge, O2 sensor, and the fuel pump. This most recent service trip, the dealer insisted that the problem is a clogged catalytic converter. Losing power on the interstate, or anywhere, is very serious and dangerous. Plus, continually being told by a dealer five times that the problem has been fixed, when it isn’t, is very frustrating. What is your diagnosis and solution?

Fuel Pressure Regulator Replacement $126.81 - $1011.90 Get a Quote
Loss of power Inspection $94.99 - $114.99 Get a Quote

I would check the fuel pressure (for being low) before doing anything else. If it is, check the fuel pressure regulator. (A clogged catalytic convertor would be a constant problem, not intermittent as you describe.) A professional mechanic, like one from YourMechanic, can help diagnose and repair the loss of power problem.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Window will not close
Hello. It sounds like the window motor failed. It is much easier for a failing motor to lower and window and not be able to close it. I would typically remove the door panel and first check the voltage at...
Fuel door release doesn't work
Hi. There are a few things that I would recommend to determine why the fuel door release isn't working. The fuel door fuse, the fuel door solenoid, and fuel door switch. Most of the time, the fuel door fuse and...
P0302 code & car makes puttering noises
Hello. The P0302 diagnostic trouble code (https://www.yourmechanic.com/article/p0302-obd-ii-trouble-code-cylinder-2-misfire-detected-by-jamahl-walker) indicates that a misfire has been detected on cylinder 2. Before changing the IAC valve, it would be a good idea to address the P0302 diagnostic trouble code and have the spark plugs...
Front end bouncing while turning from a stop
Hello there. Thanks for writing in about your 2003 BMW 745i. Many different faults can cause the vehicle to have bounce like this. The most common would be front struts (https://www.yourmechanic.com/services/strut-assembly-replacement), springs (https://www.yourmechanic.com/services/air-springs-replacement), tire balance, or a suspension arm. I...
I turn my car off n my anti theft light keeps flashing ....it has not done this before....do I have a problem
You may be having a communication problem with your key and the theft module. Try a different key to see if the problem continues. If it fixes it with the second key, then replace the key. If it is still...
Car did not accelerate. Stopped on me while getting onto highway. No fumes a d no leaks that I can see or tell of.
If the car fails to accelerate (https://www.yourmechanic.com/services/car-is-slow-to-accelerate-inspection) or is stalling (https://www.yourmechanic.com/services/car-is-stalling-inspection) there is something wrong with the fuel or ignition systems and possibly the air induction system. Only an in-person diagnostic will reveal the cause(s). Possibilities that I would initially...
My car cranks but doesn't turn over
Hi there. First, we need to determine what is going on. Does it crank and not start? or does the engine not crank/turn over? Cranking and turning over mean the same to technicians. You described it as cranking and not...

Related articles

The Best Used Cars to Buy If You’re a Wedding Planner
As As a wedding planner, the demands placed on your time are going to be significant, even if you’re only dealing with one or two couples. You need to be a master juggler when it comes to your time and...
Symptoms of Bad or Failing Brake Shoes (Rear)
If your car has drum brakes and there are abnormal noises, a reduced brake response, and a loose parking brake, you may need a brake shoe replacement.
Understanding Chevrolet Oil-Life Monitor (OLM) System and Lights
Car symbols, or dashboard lights, are a car service reminder. The Chevrolet Oil Light Monitor system indicates when and what service your car needs.