Hey guys so I have been tackling a high idle issue for a while. I have replaced the head gaskets because of cooling issues, new vacuum hoses and oil separator, new IACV, tried different MAF sensors that were know to be good, and finally bought an ecu/alarm combo from Paul Grant. After the ECU swap I had proper idle for about a month. Then last week I left the headlights on for 10 minutes at most while checking if the trailer lights were functioning. I go to start her up and nothing.. battery is dead. I jump it off and run my errands for the afternoon and didn't notice anything out of the ordinary. Well the next morning I start her up and she has high idle again but this time around 1500 rpm and its not consistent. After a short drive and restart she idles around 1000 rpm still a little high, other times after a restart I have normal idle. I put the volt meter on the battery after a drive and see 12.8v and 13.6 ~13.9v running with headlights and an A/C load. With engine off and headlights on my volts drop from 12.8v to 12.1v ~12.2v in a matter of seconds. AZ says by battery test ok but I know that's not right. I even left it on a 2 amp charge last night and within a period of 5 minutes I went from 13.0v to 12.4v. So my question is will a low battery cause a high idle? I looked in the rave but saw no mention of it.
Sorry for the lengthy post and thanks in advance!

 

I have experienced the same.