Eng Check light comes on intermitantly.
How do I troubleshoot this? Air care
failed with high hydrocarbon reading.
1988 f150 300 6cyl

 

First thing ya gotta do is pull the computer code(s) for a starting point.

 

Thanks, How do I do it? Can't find it in the manual.

 

If you havn't changed your O2 sensor in the last 50k miles or so, I would go down to your nearest Ford dealer and get a new one. That sounds like a likely candidate for your SES light. If the O2 is old it will tend to send a low (lean) signal to the PCM, which will dump more fuel into the engine. That would explain the high HC reading. Does the SES come on during a consistent set of running conditions, or is it completely random? Another possibility is the MAP sensor vacuum line. If it is deteriorated and cracked the MAP sensor will tell the PCM to add fuel.

 

Read this thread.