my 94 honda civic dx is idling to rich ... and my gas mileage is not good, not as good as it should be.. does anyone have any advice.. i already changed my spark plugs and wires, but i cant figure it out.. if any one could tell me anything that would help

Here are my possible solution with your problem
* Inspect all vacuum and PCV hoses, replace if necessary
* Cleanthe MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
* Inspect fuel lines for cracks, leaks, or pinches
* Check the fuel pressure at the fuel rail
* Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
* Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)

Hope this helps...
Good luck...

Honda guy, most hondas (true of all but the most recent generation civics) don't have a MAF sensor. There is nothing in the intake tract of this nature to clean. I hope you haven't tried taking out random parts of your car in search of a MAF.

I would start by trying to clean the IAC valve and replacing the o2 sensor. It is likely that your car is running rich not just at idle but generally (in this case the iac valve is not to blame for that). If the o2 sensor has gone bad the long term fuel trim could be messed up and causing the rich condition. O2 sensors do go bad, and I've read that the H02S from this vintage car is not expected to last too much longer than 100k miles.

You are saying that the rich idle problem is because of bad sensors. I don't know how many miles he has on his car? The year is 1994 so the mileage may be higher. That would affect the performance and gas mileage. Some people have higher mileage vehicles but in excellent condition.

First off I would make sure that it actually is rich at idle. I would then check the coolant level since these cars run coolant through the throttle body which effect the idle. The other possible cause is the 2-wire coolant temp sensor on the side of the head. If it reads too cold the ecu will richen the mixture. vacuum leak would cause a lean condition not rich because the engine is getting unmetered air not seen by that map sensor. exhaust leak and o2 sensor are also possible causes.

One of the great things about speed density fuel injection systems (map sensor), is that a leak won't throw the system off. The map sensor doesn't care where the air is coming from - through the throttle or through a leak. If the fuel metering system is in working order the mix will still be "correct".