Skip the auto shop - Our mechanics make house calls

Q: Car starts very weakly after filling up with gas.

asked by on

Recently I hit a curb in avoiding an accident, blowing the right front tire. After changing the tire, I took it in to the Subaru dealership to diagnose any problems, particularly the Check Engine light which had by now illuminated. After a few trips, replacing tires and so out, it was decided that my Engine light was the result of a bad engine fuel pressure solenoid. I had to wait on the part, so I drove it home. The following morning, I filled up, which is the first time I encountered the weak start up. The car seemed to be responding similar to a motorcycle starting cold without being choked. I took it back, and with the solenoid replaced, the light went out, and I drove home, only to find that the light illuminated again on the way home. The next day, they replaced another part in the same system, and now the light is gone. I was assured the weak start was caused by this faulty system, now replaced. However, now filling it up this morning, the issue remains unresolved.

My car has 138966 miles.
My car has an automatic transmission.

A: Hello and thank you for contacting YourMech...

Hello and thank you for contacting YourMechanic. Sometimes the gas cap vent tends to get stuck shut making the fuel system go into a vacuum. Check the gas cap for the seal to ensure that it is sealing. Make sure that you are filling the vehicle up before it hits 1/4 tank of gas. When it gets to about 1/4 tank, the fuel gets sloshed around with the junk and build up in the bottom of the tank. The pump could pick up the build up and clog the filter.

I recommend replacing the gas cap and seal first then rechecking the system. I also recommend replacing the fuel filter if your vehicle has an inline filter. The filter could be causing a restriction on the system preventing the engine from starting. If you are still having fuel issues with your vehicle, I recommend that you seek out help from a technician, like one from YourMechanic, to assist you with diagnosing your car’s starting 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!

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: Tire Pressure Light coming on

The Tire Pressure Light comes on when the air in the tire is low. If you have tested the tire pressure and it is normal, but the Tire Pressure Light remains on, you need to have the TPMS system checked...

Q: Can you drive your Chrysler LeBaron with the gas line straight without a gas filter

Not for very long before you will clog the injectors of the engine. The injectors have a very fine screen that will keep small amounts of dirt and debris that do get by the filter normally, causing it to clog...

Q: My Subaru 1998 outback dimming lights didn't work, now won't start.

Hi, thanks for writing in. This is likely a charging system issue. This can happen when the alternator is failing and does not charge the battery properly which is what causes the dimming lights and the non-starting problem. A dead...

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...
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...
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.