Skip the auto shop - Our mechanics make house calls

Q: Car is running very roughly at idle

asked by on

The other day I was driving home and the car lost power, and sounded really rough. Now, when idling it is running really roughly. I haven't tried driving it anywhere. The car is showing these codes: P0304, P1137, P0300, P1599. I am trying to figure out if this is something that I can fix, or if it needs to be done in a shop. I also need to know if I am risking damaging the car if I drive to a store for parts. I really need this car for work, and I have a long commute. Any ideas?

Hi there, thanks for writing in. Based on your faults, it seems as though you are dealing with a potential misfire causing the fuel mixture faults or fuel mixture problems causing misfire faults. The car should not be driven like this, as it can cause damage to the catalytic converter.

This is potentially something you can fix, but you’ll need to be mechanically inclined and have all the correct tools, including a compression tester and a fuel pressure gauge. Either way, the first step would be to perform a fuel pressure check and a cylinder compression check. You should also check for spark on cylinder number 4. Be careful when doing this because there is a risk of shock and of fire if any fuel was released during the fuel pressure test. These tests should point you in the right direction to diagnose your running issue, whether it be a problem with spark, fuel or compression. If these tests are beyond your scope, you should contact a professional to come to you and diagnose your rough running 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: Car shuts off while idling

Hello. This can be caused by many things on this vehicle, but the most common one is the crankshaft position sensor. I have seen many of these fail on this car and cause this. I usually use a scan tool...

Q: Gas pedal shakes when accelerating fast and misfire code came on?

Hello, thank you for writing in. The most common cause of engine or pedal shake (because you can feel the engine shake in the pedals) is a misfire. With that being said, its not uncommon to feel issues with brakes,...

Q: How hard is it to change your muffler

If you see a hole in the muffler then you should have an exhaust shop check the entire exhaust system to see if other leaks are found and what needs to be done to repair the exhaust leaks. The check...

Related articles

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
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.