Rough Idle and...

[the_hat_guy]

I have an 83' tercel, sr5, 4wd, manual 6 speed with 230k on the clock. The issue I'm having, is that it idles rough, especially on a cold start. I'm not a mechanic, but I read a lot. I figure I should ask advice before I start ripping things apart. So, the idle is a bit low, maybe 900 until it warms up, then it will be at 1000. When I am on level ground, it sometimes gets a little jerky if I'm not accelerating or decelerating. So, from what I have read, this could be that the EGR needs cleaning. The problem is, I have no idea where to find the EGR. A little advice on what I should check, and where the EGR is located would be awesome. I have a really good manual for this car, but have yet to figure out how this stuff is indexed. Anyways, you guys are awesome, just like the cars we drive

[xirdneh]

first thing i would check is the vac hose that connects the base of carb to underside of air filter housing (on driver side of carb) if it falls off car will not idle well or at all

[Gottolovem]

I agree with xirdneh
I would go get ten plus feet of vac line and replace everything ONE AT A TIME so you don't get confused I bet it will make a huge difference.
It could be something with the EGR but start with vac lines first.
Good luck

[Petros]

Most trouble with idle and running weak at low rpm is usually a vacuum leak for one of the many hoses and vac operated components. I would not necessary replace all the vac lines unless they are brittle, or crack, or damaged. But you should trace everyone one of them from end to end (inspecting for cracks or cuts that could leak), using the vacuum diagram for your model of car. Do not assume that who ever worked on your car last installed the vac lines correctly, some lazy mechanics unfamiliar with this carb and vac operated fuel and emissions system will carelessly plug them in where it is convenient.

if that does not solve the problem than check each of the vacuum components per the service manual for proper operation, a leaky diaphragm will act like a vac leak (especially the vacuum advance on the distributor). The FSM has a diagram labeling all of the components and show where they are located, there is a link to an on-line manual on this forum.

And finally there are two other areas to check, the manifold gasket where it joins the head and the carburator, and the carb itself can cause a vac leak.

If all that check out, than I have seen weak ignition coils or marginal distributor components give a weak or erratic spark at low speed causing misfires most noticeable at idle. It may need a new distributor, or internal components for it.

You must first diagnose the problem before you can fix it, none of the procedures are difficult or time consuming, but you must do them systematically (one vac line, one component, at a time) or you will not know what you are changing if you are just swapping parts out at random hoping it will fix it (that is a waste of time).

so read about the cars systems and check each one out. good luck.