E30 Idle issue when warm 87 325is -M20

[e30loverSC]

Hey guys,

Its been a while since Ive been on here. I need some input about my idle. Recently, my car (87 325is) has started idling rough. As in the car vibrates and you can hear a little misfiring in the exhaust and at low rpms if you hold down the gas a little. However, there car drives fine when going down the road. Its only when sitting still that I notice it. Sometimes when its really hot outside it will even idle a little lower than normal. But the funny part is when you first start the car cold its runs smoother than ever. Once it heats up after a couple minutes is when it starts.

Recently changed:

Plugs, Plug Wires, Coil, Cap and rotor are fairly new.

Im not sure exactly what I should replace or look at next?

[dnguyen1963]

Check the elbows going into the throttle body. Warm engine can make them loose and causes erratic idle. Once the engine cools down, the elbows becomes tight again and you have perfect idle.

[e30loverSC]

Also, When driving at highway speeds at constant rpm the check engine light comes on. When you give it more gas or disengage the clutch it goes off.

[dnguyen1963]

Pull the code and perform a smoke test with warm engine.

[Chilezen]

Check the elbows going into the throttle body. Warm engine can make them loose and causes erratic idle. Once the engine cools down, the elbows becomes tight again and you have perfect idle.

I too have this idle problem. How would you suggest fixing it? Apply some black RTV on the fittings?

Also is there a way to adjust the idle, making it a little higher?

[dnguyen1963]

Just put JB weld around the elbows. Why do you want higher idle? What rpm is your idle at?

[Chilezen]

Sometimes it sits at 550-600. Just chugs along, then I blip the throttle and slowly falls down again. Other times it will sit at a healthy 700.