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I have a 1994 MX-3 1.6L DOHC and it generally runs very good getting 300-325 miles per tank. However, when I startup the engine after it sits all night I get way too much fuel to the injectors, creating a large cloud of white/blue/black smoke from the exhuast. Also note, I now have constant problem of carbonized plugs, thus indicating too much fuel to injectors. I have replaced plugs, wires, cap, rotor, and module. Also used fuel additive and that seems to make it worse. Anyone have any thoughts? I figure it might be the BAC (Bypass Air Control) valve or ISC (Idle Speed Control) valve, but I just don't know!

I would say check you O2 Sensor, but I'm not sure. Could someone back this up ?

I have new O2 sensor, plugs, wires, cap, rotor. <P>It seems when I had it in the shop to change the Timing Belt the Timing was retarded. I didn't know this till now. <P>I advanced the timing significantly and this helps with hotter cleaner burn on plugs. No more fouled plugs. Amazing! <P>In the morning I'll find out if it also helped the excessively rich fuel/air mixture and has gotten rid of all the smoke on cold startup.<P>So far, it looks good.

Stephane '96 Balze Red RS thank you for information! <P>At this point I'm lookin for all the input I can get. <P>The car is a great vehicle, but it does have 160,000+ miles and runs very well, except for this mishap.

damn i only get like 220 miles to a tank max. what is wrong with my car!? its a 5 speed 4clyn

Well, Mr Great Tonge mine is a DOHC 5-speed and I do alot of highway miles. All stock except the rear-deck spoiler.<P>I run Bosch Platinum Plugs, Belden Premiun Plug Wires and stock cap, rotor, module.<P>I frequently replace the air-filter, change oil and filter. Run a mix of 3/4 88-octane and 1/4 92-octane. Or just use various grades of gas when re-fueling. <P>I have the timing advanced, If I recall the timing on my engine (B6E) is 7BTDC, so I advance it 3-4 degrees. If it pings too much or seems to not run well at highwayspeed I drop it back a degree or two. Also, I use Mavelous Mystry oil mixed with the engine oil to reduce sticky lifters.<P>But the biggest thing that makes a huge impact is the tire-pressure. I select quality tires and keep pressure near maximum. In my case my tries are rated at 45PSI max so I run em up to 40PSI. This significantly reduces friction between the road and tire.