because you have an engine misfire.most likely the DI cassette is faulty. (Ignition)
A bad throttle position sensor, on your 1991 Saturn, will cause the engine to run rough when it is idling. The engine will run normally at higher speeds.
your engine will sound rough while at idle speed and your gas milage will start getting worse. it also might start to backfire and make a little more noise than it normally would.
The Right Front ABS wheel speed sensor is also used as a rough road sensor to assist the knock sensor in dectecting weather there is a knock from engine or bump from the road in order to adjust the spark and fuel.
Poor maintenance and/or bad ignition coil.
You have a few things to check, first off a backfire is usually associated with a timing issue, you would notice a difference in ow the engine runs, it will lack power and be rough. Next a backfire requires unburnt fuel, so check the ignition system for problems, bad or incorrectly gapped plugs, bad wire, and if it's older look for a cracked distributor cap or worn rotor. Then look to the fuel system, it may be getting more than it can burn. Lastly valves, you may have a bent one, or one that is not opening or closing completely.
A timing chain, that needs to be replaced, can cause your engine to run rough and lose power. A broken timing chain can cause significant engine damage.
Car will run rough ,backfire and you may be able to here it rattling.
the check engine light is blinking and my 03 Nissan exterra is running rough
Only rarely is the adjective "rough" preferably used as an adverb (e.g the engine still runs rough). The usual adverb is "roughly."
because that's kind of a big engine
More than likely ignition timing..
the engine will seem to cut out or run really rough
Could be broken trans mount or engine mounts. Not sure what is meant by riding rough.
Engine miss/running rough. Engine back firing / poping
Check engine light, low power, no start, runs rough, bent valves,Check engine light, low power, no start, runs rough, bent valves,
most likely your coolant sensor is bad have it checked and see if the harness is corroded Could also have spark problem with your ses light on/off You may have corroded coil towers causing a misfire
when stopped at red light or when in park
vacuum leak,map sensor
this could be due to either burnt valves, or valve seats. other then that, the cylendar is getting too much fuel.
have vehicle scanned to determine the problem
No, on a fuel injected engine it can cause high idle speed.
you probably got a cracked head
Power brakes use engine vacuum to get their power. If the engine is out of tune, the loss of vacuum will cause it to run rough. Try changing the spark plugs.
There are many things that can cause a rough idle on this car. The computer could be going out, the engine may not have enough oil, and the engine may not be getting enough fuel or electricity.