2002 Ford Explorer

Engine Mechanical problem
2002 Ford Explorer 6 cyl Four Wheel Drive Automatic 72000 miles

I have a 2002 Ford Explorer Sport Trac 4.0L 4x4 with an apparent engine problem. The symptoms are a check engine light, intermittant rough idleing, and diagnostic fault codes of P1151 & P0174. The big clue however is an intermittant, strange but potent odor from the exhaust. I know the problem occurred all at once as I smelled the strong odor immediately. Since the occurence happened the odor is come and go. From research, I gather the codes are from the oxygen sensor on the 2nd bank prior to the cat converter, and that I should check the EGR, a potential vacuum leak, and the air flow sensor. All seems to be okay, but I'm wondering if these are all symptoms of a more serious issue. I'm somewhat dobtful an odor like this could be caused by a improper gasoline mixture. Can you help? Thanks in advance for the helpful info!

July 10, 2010.

Hi: Is the smell that of sulfer / rotten eggs?

Regarding the question of type of smell, yes, the odor does have a sulfur(ous) quality. Doesn't appear to be burning engine coolant. No white smoke, water vapor or dripping from the tail pipe, and no loss of engine coolant. During the first occurrence of the problem, the odor was very strong, but no engine light. Now there is just a slight odor with the constant engine light. Sorry for the late response. Been out of town. Thanks for the help.


Jul 18, 2010.
I need you to check the computer for codes. Most parts stores will do it for free. It sounds like the catalytic converter may be plugging. If I had to guess, I think you will find you have a bad O2 sensor that is causing the engine to run rich. That is what most likely causing the light to come on.

Have the computer scanned and let me know what you find.