Engine running rough sounds like a sensor (possibly the O2?) The gauges pegging low sounds like an electrical short. The SERVICE ENGINE SOON light should come on, so read the codes to see what it might be.
incomplete combustion of fuel
A faulty gas cap could cause the check engine light to come on but it would not cause a rough idle or engine noises. Start with having your local auto parts store read the codes. The codes will help determine why the check engine light is on.
if you have a carborator, it may have to be adjusted
It absolutly can. if the tank was not filled up prior to to sitting condensation will form causing water to mix with fuel. even a small amount of moisture can cause the engine to run rough.
Have vehicle scanned to determine the problem
yes it is possible
Pressure test the convertor.
The engine may be low on oil, when you make a turn the oil pickup tube sucks air and the oil pressure drops. Check the gauges when the light comes on, one of them is out of range.
a plug misfiring would cause the rough idle and check engine light or if u changed the plugs and wires u could have put the plug wires in the wrong order
Check the Cats have not disintegrated.
my 1990 300zx is idling rough what could cause this?
Engine is running extremely rich.