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Category: Acura
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Acura MDX

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I have 2003 mdx with poor fuel mileage and sluggish acceleration. Highest speed possible is 130km/h when accelerator is floored. What could be the issue?

I've been told to replace cam angle sensor as well

hello and welcome to,


How many miles on the vehicle?


what was the last major service you performed?


is the check engine light on?

Customer: replied 3 years ago.
137k miles.

Last service was regular oil change, replacing nozzles and installing racing switch.

Check engine light is not on. Was showing misfire in 2 cylinders, cleared it 5 days ago and it's not come back on.
what exactly are you calling the "racing switch and nozzles" ?
Customer: replied 3 years ago.
Technician called it a racing switch/sensor. It's located close to the oil filter. The nozzles are the 6 filters through which fuel is fed into the 6 cylinders.

oh ok you are talking about the fuel injectors and the vtec switch i believe


were there or are there any codes stored in the pcm?


You replaced all the catalytic converters?

Customer: replied 3 years ago.
Those are the names, yes.

There are no codes at the moment.

I replaced the whole catalytic converter unit. The engine check light went off after the replacement. This is the unit under the car, connected to the exhaust.
but there are technically three converters, two right at the exhaust and the third is in the pipe
Customer: replied 3 years ago.
The one I changed was around the middle of the pipe.

Could a fault with the other 2 cause the car to be sluggish, have very poor gas mileage and never exceed 130km/h speed, even withe engine check light being off?

yes it is very possible. but i would have guessed that the check engine light would be on.

clogged or partially clogged converters can cause all these symptoms.


you will need to physically remove them and look at them to see the condition of the internals.


please do not rate my service until we are completely done with your concerns. ask as many question as you want before finalizing your experience. thanks

Customer: replied 3 years ago.
Fair enough. Is there anything else that could cause these symptoms? I would like to check all possible issues if possible.

Also would I need to replace the cam angle sensor as the technician says?

not if there was ever a code associated with it and especially if after you cleared the codes and none came back


also check the spark plugs and if there is any doubt of the cam angle sensor then i would definitely check the timing belt timing and make sure it is good.

HONDASERVICE7791 and other Acura Specialists are ready to help you
Customer: replied 3 years ago.
I have checked all the above. They are in good condition.
the two converters that are on the motor are ok? have you removed them and tried to accelerate again? no more codes?
Customer: replied 3 years ago.
They are ok. I did. Still no codes. Throttling while stationary the engine is revved up to above 5rpm

I'm hoping you mean 5,000 rpms......


if there are no codes, the converters are clear, then i would investigate the condition of the fuel and make sure it is not contaminated

Customer: replied 3 years ago.
I mean 5,000rpm. Thanks for the suggestion about the fuel but doubt that's the issue.