Engine Performance problem
1994 Buick Regal 6 cyl Front Wheel Drive Automatic 126555 miles
i have a problem with the hydrocarbons limits in my city 220ppm is accaptable my car is att238ppm. I took it on the highway thinking I could blow it out but it went up higher to 293ppm I would just like to know what I should start to try to fix this problem
Elevated hydrocarbon (HC) emissions usually indicate ignition misfire due to fouled spark plugs or a bad plug. But high HC emissions can also be caused by burned exhaust valves (check compression), lean misfire (check for vacuum leaks, low fuel pressure or dirty injectors), or rich fuel conditions (fuel saturated carburetor floats, excessive fuel pressure, leaky injectors or a dead O2 sensor).