94 Ford Escort, Check Engine Light on Sometimes

by Nicole Pride
(Ontario, Canada)

My 94 ford escort check engine light is on sometimes but shuts off on the highway or when I'm going up a hill (if its on) but most of the time its not on. My coolant light has recently been flashing on sometimes but hasn't stayed on yet. My car idles really rough and I have changed the spark plugs, cap and rotor, valve cover and tranny pan gasket. I noticed a very small rattling and a power loss when climbing hills sometimes. Very rarely it bogs out when I start it and almost die but then I tap the gas very lightly and it revs up to normal idle speed. Sometimes it idles at 2000 and others its only 1000. Could my battery post corrosion have anything to do with this or is it the IAC?

Steve Says,

Thanks for asking me your question. The first thing that needs to be done is to have the codes checked. Since the check engine light has come on (even though it doesn't stay on) that means that there are codes stored in the computer. Most auto parts stores and many repair shops will do this for free. This will be the biggest clue into why your car is running like it is.

If your battery posts are corroded then they need to be cleaned. While this might not be the cause of your problem it could be, and if you do not clean them then it will probably cause a problem in the future.

The idle air control valve could definitely be to blame for the idle problem, but I would not worry about that too much until you repair the problem that is causing the code to come up. After that is fixed, if you still have an idle problem then you can work on diagnosing that.

I hope this has helped. Please post the fix when you know what it is. Thanks