Skip the auto shop - Our mechanics make house calls

Q: car running very rough, making oil 1990 Nissan/Datsun 300ZX

asked by on

The car was running great. The next morning when it was started it was smoking very badly and barely ran. I checked the oil, it is over full and smells like gas.

My car has 70000 miles.
My car has a manual transmission.

Hello - I suspect your cold start system has gone "full on" or you have leaking injectors. Without question your fuel system is pumping way too much fuel into the intake, leaking past the piston rings, and entering the crankcase. I would recommend a engine fuel system inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

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: why does oil pressure gauge go up and down with rpm of engine?

Have you had any part changed in the recent past like an oil sender? If you did then you may have got a sensor without a sensor regulator built in. If the sensor was not replaced then try replacing the...

Q: I have rotated my engine by hand for several minutes and still can't find TDC. My car running fine I only changed my water pump.

You should replace the timing belt if it got wet with coolant or it will fail prematurely. The timing marks shown here will align only every two revolutions of the crankshaft.

Q: Fuel gauge not working

The engine control module would need to be scanned and the PID looked at, to see if the fuel sender is sending a proper signal to the powertrain control module, or the sender is open, causing the wrong reading. The...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...
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.