98 Integra LS mis-fire problem

[themonsteraria]

I'm usually on the Civic forum, but I have a friend that needs some help with his Integra. He has a 98 Integra LS that runs great while it's cold, but as soon as it heats up it starts mis-firing. But it only mis-fires when the throttle is not open. So, if he backpedals, then it mis-fires, or if it's idling, then it mis-fires. I asked a Acura buddy of mine, and he said it was the main-relay, so I replaced that, but it still has the problem. I was thinking that it could be an O2 sensor, or a clogged CAT, but I'm wondering if anyone has any knowledge to drop here. P.S. I seem to remember a post about this somewhere, but I couldn't find it using search, so if you know where it is, please direct me... Thanks

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[cruzalekz]

dont change any sensors specially if the check engine light is not "on".

when cold, offcourse the rpm is high so you dont feel the misfire.

if the light is not on, you could try a full tune up... means plugs, wires, cap and rotors and fuel filter.

if that dont work, might be mechanincal

[themonsteraria]

The first thing we did was a full tune up. Didn't help.