Engine Mechanical problem
2003 Dodge Durango V8 Two Wheel Drive Automatic 53000 miles
Scanner shows code 301 cylinder 1 misfire detected, 456 with EVAP leak small detected, and 442 EVAP emission Control System purge small leak.
At start up engine RPM is normal for about 15 seconds then RPM drops, when I turn on the A/C the RPM's increase to normal. What do you think it could be spark plugs, oxygen sensor or something else. Also about a year ago the camshaft position sensor failed and was replaced.
A bad evap leak will cause all of the above sean. The a/c forces the computer to raise the rpm to run the a/c properly which overrides the low idle from the evap leak. You could also check the idle air control valve and clean it out if its gunky. If the engine hasnt had a tune up by now, it needs it anyway. Proper maintenance in a timely manner will prevent these problems in the future.