Skip the auto shop - Our mechanics make house calls

Q: 94 lexus will not exceed 40 mph and very slow

asked by on

What could be the problem

My car has 160000 miles.
My car has an automatic transmission.

Hi There, There are a number of things that may prevent your car from not exceeding 40 mph, such as a faulty transmission control module or potentially a failing catalytic converter. The catalytic converter converts toxic exhaust gases into less harmful pollutants that are suitable to be expelled into the atmosphere. When the catalytic converter is clogged, this causes these gases to be backed up into the exhaust system not allowing the engine to breathe properly. When this happens, the engine is forced to work much harder to expel these gases. This often results in the engine bogging down, hesitating, shaking and causing very poor fuel economy. This should also cause a check engine light to come on as the O2 sensors should be reading the incorrect amounts of oxygen in the exhaust gases if this is your problem. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your catalytic converter.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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

Get a quote

What others are asking

Q: My car is not getting power and it's hard to change gear from 2nd I think I need a new air filter.

Hi there. It is very possible that your vehicle needs a new air filter and spark plugs. When you inspect the spark plugs, take a good look at their wires. Are the boots and wires in good condition? It's also...

Q: Braking car quits running

A few different faults can cause the vehicle to die when the brakes are pressed. The most common would be a vacuum leak or a brake booster failure. Either of these can pull too much air and can cause the...

Q: we replaced the batteries and got all new heavy duty cable wires, truck will not start just makes a click sound.

Hey there. This is a common issue on many vehicles when the starter relay is bad. This is a small unit on the starter that directs power from the battery to the starter causing it to engage the flywheel as...

Related articles

P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.