I recently bought a 1989 Accord exi w/auto trans and a/c. It has 182,00km on the odom. This summer it had a no start when hot condition which was fixed by changing the main relay. Now the idle drops from around 800rpm to 400 rpm with lights on and brake pedal depressed in gear. By putting it in neutral and touching the gas , it stabalizes untill it's put back in gear. I've tried turning off the lights and shifting to neutral but I still have to touch the gas otherwise the computer kicks the idle up to 1200rpm and then it drops back to 400 several times. There are no trouble codes and no vacuum leaks. Help!!

 

Try bumping the idle up a bit by turning the idle speed adjustment screw on the throttle body (flathead, about 1/2 in diameter, on side top of TB right above braided red hose). Turn counter-clockwise to raise idle

 

Thanks for the tip. When I got the car it would bang when putting into gear so I adjusted the linkage and the free play on the detent cable. It shifts fine with no clunking but since then it's had this rough idle problem. They must of raised the idle by the throttle linkage so it's had this problem for awhileI would assume.I'll give it a try