I have a '91 accord, 5-spd and I'm trying to replace the o2 sensor. This is the first honda I've ever owned, so I don't know much about them. There is a heat shield that sits over the headers and directly on top of the o2 sensor. I've tried to take the shield off but it seems like the a/c hoses are keeping me from taking it off. Is there another way to get to the sensor? Something I'm not seeing? Any help would be greatly appreciated guys!

 

I think there is a cutout on the shield, with an O2 socket-rent or buy one- you can remove it without removing the heat shield.

 

Thanks. Well, I got it out and replaced the o2 sensor, I also cleaned out the IAC valve. My idle seemed normal for about an hour, then it began jumping up and down again, any other ideas what it could be? I'm all out of guesses and can't afford to take it to a shop.

 

Sorry, didn't know the original issue........Any stored codes? Any recent work done?

If none, IAC is good and coolant level is fine, no trapped air. Have you cleaned the air boost valve?

 

Is there an FITV on the '91?

 

Sounds like a vacuum leak to me, especially if the idle or RPMs are surging up and down in a rhythm.

 

There are three valves. IAC, FITV, and the air boost valve. Any one can cause an air leak. This has been covered a bunch on here, so search around.