What' wrong with my Moms Achieva?

[wibblersnatch]

Ok, my mom has a 93 olds achieva. its a 4 banger but its eating gas like an 8,it gets worse gas mileage then my DSM! I replaced the map sensor and the plugs but its still eatin gas and smokin like a steam engine. Anyone know whats wrong? I'm leaning toward the O2 sensor but im not that smart. Any help is greatly appreciated.

 

[turbolover2]

They get a lot of vacuum leaks. Check for that. If it's misfiring, it could be a bad coil (they go bad a lot also on those cars). I really need more info to help.

 

[markmakeitso]

It could be the O2 sensor, since those tend to cause the engine to run rich as they go bad. Depending on the sensor it could be an easy fix (15 minutes and $25) or quite a bit more painful ($100 and...probably still about 15 minutes). What did the plugs look like when you pulled them, and does the car still have the same power as before the mileage went south?

 

[wibblersnatch]

the plugs were black. and no, it doesnt have mcuh power. u have to put it to the floor to get it to go anywhere.