Q: check engine light on, 1990 Subaru Legacy

asked by on

Loses power when going long steep hill. Sta.wagon has slightly strong fresh gas emissions. Replaced knock sensor, spark plugs, oxygen sensor, cleaned mass air flow sensor. Replaced fuel injectors.

My car has 140000 miles.
My car has an automatic transmission.

Hi there, thanks for writing in about your 1990 Subaru Legacy. You need to have the fuel pressure tested to see if the fuel pressure is within specifications and will hold pressure after testing with engine off. The fuel pressure regulator may be leaking excess fuel into the [intake manifold causing it to run rich. Scan the computer to access codes and diagnosed them as needed. Make sure there is no leak in the intake hose between the mass air sensor and the throttle body. If you need to have this done, a certified technician from YourMechanic can come to your home or office to inspect the Check Engine Light and let you know what should be done.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 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!
  1. Home
  2. Questions
  3. check engine light on, 1990 Subaru Legacy

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 lacks power during acceleration onto freeways

Hi there, thanks for writing in. If the car was misfiring, there would be a check engine light that is flashing, or at least illuminated while driving. Since there are no lights illuminated on the dash, it is most likely...

Q: Check Engine light with error code P0773

You are correct to move forward with the diagnosis that the code P0773 on your Ford F150 indicates that there is a problem with one of your shift solenoids. In order to move onward with a proper repair, the transmission...

Q: Car is losing power and shaking

Hello. Your intuition is correct. Your vibration is caused by a failing "flex disk", a large rubber and steel "doughnut" which connects the transmission and driveshaft, and acts as a u-joint to allow flexing as the engine and transmission move...

Related articles

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...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...