hey all, newbie to this forum. we just bought a 98 EX. it's in cherry like condition, but after my gf took it out the other night, she told me that the CEL was tripped but that the car was running fine. i took it for a spin and noticed that the idle becomes noticeably rougher once i switch the AC on while at stop.i wont be able to get the codes read until later on in the week, but i was wondering if anyone else has an idea of what may be causing this, or if this is a well known or common problem in these vehicles. i wouldnt call myself a gearhead by any means, but i am fairly mechanically inclined and understand your basic car jargon im not afraid to turn the wrenches, so fire away if you have any opinions, or info. thanks in advance.

 

Well I can't help you with the code issue as you don't know what they are as of yet but the additional vibration with the AC on at idle is pretty normal.

The compressor is placing an additional load on the engine and at idle RPM this causes a vibration because of the low engine speed.

This vibration shouldn't be significant however, unless you have an 8 lb. flywheel like me and solid motor mounts in which case it feels like theres an earthquake under your hood

 

thanks, ive just never had a car that idles this rough once the ac is flipped on. im going to get the codes read in the next day or two. is there a thread that has a listing of the codes on this forum? thanks in advance.

 

Google the codes....if you don't have a manual.

When was the last tune up done?

 

You bet, spend some time getting used to the search function on the forum and it will help you a great deal, but since you're new, here ya go

https://honda-tech.com/forums/honda-accord-1990-2002-2/check-engine-light-codes-cel-diagnostic-trouble-codes-dtc-malfunction-indicator-light-mil-1490107/

 

thanks guys. i just bought a new OBDII scanner and i got the P1259 "manufacturer control" message. anyone have advice on where i should start to troubleshoot this?

 

start here
https://www.google.com/search?source...=UTF-8&q=P1259