Q: Rough idle, smoking,CEL on

asked by on

My 2000 celica is smoking, getting misfire codes and idling so low that it dies. Pulled codes (p0300,301,303,304) replaced all plugs and checked coil packs(good). There is lots of smoke and the smell of gas is terrible. I looked around for possible exhaust and air leaks but found none. Please help

My car has 150654 miles.
My car has an automatic transmission.

Hi there. The P0300 OBD-II trouble code typically indicates that there is a misfire in random or multiple cylinders. The other codes indicate that the misfire is being registered in the first, third and fourth cylinder. This is most likely why you’re engine is running rough. The best thing to do is have a professional mechanic complete a car is running rough inspection, so they can determine why the cylinders are misfiring and causing the symptoms you’ve described above.

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. Rough idle, smoking,CEL on

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: Over heating coolant not siphoning back into coolant over flow tank

Hey there: It's common for many mechanics to make the mistake of mis-diagnosing the cause of an overheating situation; especially when they assume it's a thermostat issue. The problem could be caused by a blockage in the coolant tubes running...

Q: 2012 Elantra - I'm changing #4 cylinder ignition coil but i'm not sure which one it is. Anyone know the cylinder order?

The No. 1 cylinder is the cylinder nearest the engine's crankshaft pulley. The No. 4 cylinder would be nearest the other end of the engine which is the flywheel (or flexplate) "end" of the engine. If you need assistance with...

Q: The car I'm interested in buying has an engine knock

Engine knock by definition means the combustion taking place is mistimed or improperly detonated. More technically it means the explosion(s) has taken place partially or completely outside of the "envelope" (or area in the cylinder that is designed to push...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
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...