Skip the auto shop - Our mechanics make house calls

Q: Check engine light on, lost engine power 2x, now get 5-6 mpg less..ideas?

asked by on

The check engine light has been on for quite a while, in the last 4 months the engine has lost power 2x, so I stop and restart to reset whatever needs to be reset. Now I'm getting 5-6 mpg less on my last 3 fills. Nothing else has changed. Tire pressure is where it's supposed to be. Once my mechanic referred to it being one of 2 things, he said they were side by side and had something to do with fuel evaporation. Any help would be great.

My car has 170000 miles.

You will need to have the engine computer scanned again to get the codes and then properly diagnose any codes that are received.

Fuel evaporative codes may cause the truck to run richer than normal but should not cause the drop in mileage you see. There may have been another failure and an additional code stored. This is why it should be tested again. You may have caused problems with the O2 sensors or catalyst damage from driving with the other problems for an extended period of time.

I’d suggest having a certified mechanic diagnose the trouble codes again to pinpoint the root of the issue.

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!
  • Home
  • Questions
  • Check engine light on, lost engine power 2x, now get 5-6 mpg less..ideas?

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: Car not starting up

Hi there. In order for a vehicle to start three things are necessary: fuel, air, and spark. If one of these three are absent your vehicle will not start. A certified mechanic from YourMechanic can correctly diagnose your vehicle.

Q: Ticking noise from tire

Hello! That is usually an indicator of a faulty wheel bearing. The wheel bearings on Trail Blazers will go bad usually in about 25,000 mile intervals. The wheel bearings are bolt on bearings, a rather good design, but they tend...

Q: Check engine light is on - 2011 Nissan Altima

Hello there, thank you for asking about your 2011 Nissan Altima. It's hard to say exactly what the shop you spoke with quoted you for, or where they were getting their parts and labor estimates from. Usually the parts are...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...