02 Camry p0300 code
 

Hi guys,
I'm having problems with my 02 Camry. My check engine light and fuel light both came on at the same time. I had about 1/8 of a tank of fuel left which is more than normal when the fuel light comes on. I refueled and the fuel light went off but the check engine light is still on. The code reads p0300 which is multiple random misfires. I checked with the dealer and was told that there are multiple possible problem wih that code. I cleaned the mass airflow sensor, replaced the plugs.
When I start it it runs rough until I rev the engine up to about 2700 rpms. If I press the accelerator pedal and hold it down the rpms increase to about 3500 then immediately fall to about 1000 before returning to 3500. This continues until I release the accelerator pedal.
Any suggestions would be great
Thanks
Josh

What engine model, 4 or V6 cylinder?

Fuel level light indicator system is on an independent circuit, not monitored by check engine system.

Engine idle and operate rough both hot and cold?

Sorry I guess that would be pertinent information. 4cyl runs and idles rough both hot and cold. I think that I may have it isolated to a bad igniter coil but won't be able to replace it until tomorrow

You can remove each coil from the head, crank engine and do a spark test.

I replaced the faulty coil. Check engine is now of but the engine idle is now about 100 rpms. What caused this?

Beside the low idle does the engine now operate OK when given the gas?

Check engine light is off? Check engine system needs time to complete its tests which are run typically twice over a preset number of driving conditions. If you didn't fix the problem the check light may return after the test are completed.

Did you disconnect the battery, if so this can result in the computer needed to relearn the correct idle RPM. This takes a few engine starts and perhaps driving a little to correct itself. If the problem was fixed, the idle should reset to normal after a short time.

If you did not disconnect the battery then not sure. This engine uses an electric throttle where idle is set by the computer. Just changing a coil should not result in changes to the idle speed. Given past experience assuming nothing else was disconnected, changed, etc and you fixed the problem the idle RPM may work itself out. Suggest not digging into the engine at this time unless looking for a disconnected hose, plug, etc.