Still Idle issues

[kakarot135]

Okay I have a 93 1.6 sohc that I have been having idle issues with, especially when at a stop with the clutch in and on the brakes. The idle will start at 800 rpm and drop to 200 or so then back to 800 and then 200 and so on and so forth. So Far I have tried the following fixes.
90 amp alt from v6,
New cap, rotor, plugs and wires,
checked timing and adjusted(advanced slightly)
increased the idle slightly (from 700or so to 850)
Any other ideas as to what could be causing this issue? The only thing that I can think of is that it is my Idle air control valve. does any one know of a way to test this part? I am getting pretty confused as to what the problem is and any help would be appreciated.


Jason

[coindex]

A main cause of idling issues especially at sitting is a cause of a faulty MAF sensor. (Mass air flow sensor). If you don't know which sensor im talking about, it is the sensor connected to your air intake pipe by your air cleaner.
Take that out and check it.
Hope that helps ya.

[andre44]

hey kurt, i have a 93 1.6 with the same problem, I got a MAF from a junkyard which helped a little bit... because i had the same problem but it wasnt as bad, it got worse and worse and then i exchanged it for ANOTHER MAF at the junkyard because i had a 4 month warranty and it improved the problem a little bit again... but im sure it will get worse yet again... so you'd probably be better off jsut getting a new one.

[OROutdoors]

This kind of problem can usually be narrowed down using a vacuum tester (costs about $20.00 at most auto parts stores). The manual that comes with the tester usually has some good suggestions based on the results. Every Chiltons and Hayes manuals also has a results chart.

MAF is a good place to start.

You may want to also check your exhaust system. Temporarily loosen bolts between the exhaust manifold and the pipe that leads to the cat -- enough to let some exhaust out -- then test the car again. This will be loud if you gun the engine, but should be okay at idle. If the car idles normally, you have an impeded exhaust system. Remember to re-tighten the bolts before you drive it again.