Why does my idle suck?

[Cool Mr Steve]

When I start the car my idle sits around 1100 - 1200 rpm (when warm). After driving for a bit it seems to sit around 1400 - 1800 rpm. Sometimes it drops lower, but usually it sits pretty high while driving. My throttle body is extremely clean, my ISC is good, but my EGR says it has something like "Low Circuit Input". Also, I have very low vacuum. Could the EGR be causing it? If so, should I just block it off? P.S. Don't try to diagnose the low vacuum... I've asked on these forums WAY too many times, and nobody seems to want to give me the answer I want.

 

[rgurleyjr81]

Have you checked for vacuum leaks? If you haven't done so, maybe you can bypass all the emissions and the EGR valve. I know at one time, my ISC went bad which caused it to idle high like yours is doing. Just a couple of ideas.

 

[oldman]

P.S. Don't try to diagnose the low vacuum... I've asked on these forums WAY too many times, and nobody seems to want to give me the answer I want.

What is the answer that you want? What have you try already?

If a boost leak test is not on that list, I would strongly suggest doing one.

 

[Cool Mr Steve]

Boost leak test done, vacuum leaks checked, Cam timing checked, fuel mixture checked, throttle body plate and ISC checked... Anything else I can check for? I'm out of ideas and nobody wants to answer me when I post my problem... Is it possible I have aftermarket cams? I posted last time how my cam timing marks, when I got my car, were angled in (I.E. the exhaust was one tooth clockwise and the intake was one tooth counter-clockwise). When I recently did my timing belt, I replaced them to stock settings, where the timing marks lined up... After that, I had low vacuum. Defiant said that it was probably because I angled them back that I have low vacuum, but I have no idea why these abnormal cam settings may have caused good vacuum, whereas the normal cam settings are causing bad vacuum (12-14 in/hg at idle).

 

[Cool Mr Steve]

This is why I said disregard that part, because now no one can/wants to answer my thread. I really don't want to have to take it to the shop, but there is no other option I can see.

 

[oldman]

Well, it does sound like a very complicated issue and you seem to have most covered, I doubt most shops will be able to find your problem either. Have you check compression yet? During your pressure test, any leakage through valve seals? Have you try contacting the previous owner about the cams?

 

[ACKERSON]

If your cams were degreed and you change the position of the gears then you could experience the same symptoms you are having now. Also you can have slightly bent valves and it will do the same thing and yoyou might not notice it. Keep in mind I said SLIGHTLY bent. Some people have had similar problems and taken their head apart and found they had slightly bent valves, even with normal compression.

 

[Cool Mr Steve]

Hmmmm.... That sucks, kinda... My compression is about 190 across, but I guess it is possible that my valves could be slightly bent. Would there be any other way of knowing other than tearing it apart?