Smoke coming from exhaust

[Deadrodent]

While trying to fix my idle tonight (which i partially fixed) I noticed that when I rev my engine black smoke shoots out the exhaust. I'm thinking this means I'm running rich but my gas mileage is fine (probably about 22-25mpg). My car's exhaust does smell strongly of gas however plus it seems my engine is misfiring. Every few cycles the engine will kick and return to normal...i can feel the kick through the shifter and the pedals. I'm thinking that maybe my o2 sensor is blown up which is causing the engine to run rich? I'm going to check the spark plugs tomorrow to see if i can read anything from them. hopefully i'll be able to diagnose the problem soon. i don't want to get another freaking ticket if i'm blowing smoke out my exhaust...

[1991S13]

You're on the right track - check the plugs and wires, o2 sensor, and the MAF.

[Deadrodent]

any other ideas on what could make my car run rich/spout blackish smoke WITHOUT messing with my gas mileage?

[:: orion ::]

Bad fuel pressure regulator...would run rich at idle, but fine otherwise...

Get a cheap fuel poressure gauge, and check to see if you have 43.5psi at idle with vacuum line DISCONNECTED, or ~35psi with the vacuum line connected as usual.

- Brian

[Deadrodent]

where do i hook up the fuel pressure gauge?

[KADreams]

Have you tried wiggling all the harness connectors with the engine running at idle? Many of the connectors are known to corrode, especially the coolant temperature sensor harness. This could give you an intermittent rich condition.

[tiger]

Hey hun, you could have an injector stuck open... I had that happen on my SR... black smoke, horribly strong smell of fuel from the exhaust.. go over to the injector harness and unplug one of the injectors one at a time to see if your idle changes... if you have no idle change on the one you just pulled out.. .something is wrong with that one! If that wasn't the problem... I would go with what KA dreams said.ECT sensor. When I got my ka and smelled the fuel in the exhaust I went to check the forums and I saw that it was a possible ECT sensor... I checked mine and it was frayed right off...I fixed that and no more fuel smell in exhaust.