It is entirely possible your thermostat is not functioning...probably stuck in the open position. This would allow your coolant to constantly circulate and therefore never heat up. This would result in little or no heat especially when cold. It would also never allow the car to reach "operating temperature" which is probably 160-180 degrees. This would tell the computer control the wrong information....air/fuel mix, choke settings, etc....resulting in poor performance and probably poor mileage also. Replace thermostat and gasket, fill with fresh coolant in the proper mixture and see if that helps your situation...good luck! I have a 92 Lesabre and it was idling rough and sounded like it wanted to stall at times, after I changed plugs and wires. The idling problem I solved. There is a vuccuum line that runs to a canister located under the hood in front of the tire well/driver side, actually there are two lines in which one was completely missing, its about 1/4 inch 12-15 inches long, the other line is a bit larger than 1/4 and it was in place. You are probably getting poor gas mileage as a result of this missing line also.I replaced it, I work for a company that sells hoses so I got it for free. I'm sure it will be very inexpensive to buy. I also have the heating problem. I get warm air when its not cold outside from my vents and cool/cold air from the floor blower. I flushed the heater core, it was not clogged -all ok-heater hoses, coolant ,radiator hoses, thermostat, no leaks. "I think I have narrowed it down to the computer module behind the glove box or the small motor supposely connected to this module". I hope that helps you,its about to get cold, bye. the cold air from the floor vents is usually caused by a leaky vacuum tank in the engine compartment.
Engine will run lean. It will idle rough, have less power, & use more fuel.
Check your spark plugs and fuel filter.
I think you might have a bad head gasket. Just a guess.
Had the same problem with my 2003 Axiom... It was my intake gasket. 50 dollar gasket.... easy fix
Stalling rough. Like stalling while on a hill. That made mine skip.
That might be the PCV pipe or some other vacuum leak. That will cause stalling.
Most of the time rough running and stalling is due to vacuum leaks. There is more of a load on the engine when it is in gear, so that lends itself to stalling out. When I look for vacuum leaks, I have the engine idling (maybe you need a friend to keep it from stalling) and then spray carburetor cleaner around the various hoses & gaskets that could be leaking. Any increase in the idle speed would be an indicator that you have a leak in that area.
your idle settings might be to low. check on your engine near your carb for a small screw that is all by itself
A bad cdi, will cause no spark if its completely bad, but if its going bad can cause misfires, random stalling and rough running, like alot of backfiring and stuff.
Fuel pump sensor relay
300zx twin turbo lots of black smoke and running rough
Poor fuel miliage, rough idle, no start, poor acceleration, stalling.