1994 nissan altima rough idol when stoped runs

find out what's the trouble code:
http://forums.nicoclub.com/how-to-read-obd1-trouble-codes-for-1993-1995-j-s-t217489.html
then post back

The valve cover gasket has nothing to do with the engine running rough. It simply seals the mating suface between the valve cover and the cylinder head. When bad, it will leak some engine oil. It will NEVER cause your problem. I suggest taking it to a reputable repair facility, and never return to the place that gave you the first diagnosis.

Your idle air control can be of non operational,a good throttle body cleaning will help you , also a open EGR pintle that didnt close properly that leaks vacuum into the engine can cause the rough idle

Check the fuel lines in the engine compartment - look for leaks - also check the fuel line from the fuel filter - most commonly located on the driver rear side, just behind tire. Also, consider replacing the fuel filter.
Please let me know if you need further assistance.
carsandcomp,
Guru, Premium & Phone Expert @ Fixya.com

Ok! BIshercf,
I'am listing some things for you to check, I feel is not a big problem.
1)--check for cracked or bad vacuum lines. Possible vacuum leak!
2)--check for plugged fuel filter. The do plug up.
3)--check for a bad fuel regulator.

Let me know how you do. I hope this helps.

can be a few causes such as cracked block -cracked head- head gaskets -manifold crack

check your EGR and for vacuum leaks

I have a '94 Altima with 2.4 liter 4 cyl. engine. At around 150K the timing chain and tensioner were replaced - should solve your problem, too. If you're sure the chain is rattling you should really get it serviced now, not later. Also, if your car is running rough it could be more than just the chain and tensioner; it could be your ignition system, such as plugs, coil, distributor, etc. Bottom line is, your car needs to be checked out right away.

yes the alternator can send dirty ..too high...or too low a voltage to the system causing all sorts of gremlins.. test test

yes replace the brak sensor on the pedal...