I figure anyone who can answer this is hard core Honda.
I have a 91 Civic LX, 1.5 liter, manual 5 speed, AC, power steering, windows and door locks. It has an erratic gas mileage and idle problem. Anytime it sits in the heat after being run, when it is first turned on, engine already warm, will idle at 2k until it runs a distance. It seems like something overheats and then cools down once air starts moving. Strictly a warm weather problem. Also, after idling in the heat for a while the AC just cuts off AND the cooling fans quit too. The only thing I can do in traffic is turn the heater on wide open until the fans decide to come on.
Next, maybe related, the gas mileage is all over the place. I commute 168 miles a day, same traffic patterns, same roads. Yet on Monday it may be 37 mpg and the next 30 mpg and on Wednesday back up to 35. I?d say the average is around 34.
Background: Car owned since new, 309k miles, replaced alternator, distributor, primary fuel injector and EACV. The O2 sensor replaced several times and the ECU was swapped just to see if it makes a difference, no it didn?t. If you need further details or history please let me know.