So I finally got my daughters 88 jeep wrangler running and I've been driving it most of the week. the other day it started to develop a pop out the exhaust everyonce and a while in between shifts. it dieseled on me twice when I shut it off. it is a 88 2.5L TBI motor. I borrowed my buddies snapon scanner and I'm able to see good amount of data. bascally when I start it it will go into closed loop and stay there until the engine gets up to operating temp. then it will switch to open loop and lock short term BLM to 128 but long term stays at 172. I can watch the o2 voltage swing back and forth normally. If I take it out for a drive it will stay in open loop once and a while it will go to closed loop, but won't stay there long. just looking at the o2 volts everything looks like its working. I had a buddy tell me that he thought that jeeps idled in open loop, but I can't find much on this topic. I think mainly because not many people have the capabilities to read data from these things.
does any one know what the stratagy jeep uses on these things for determining when to go closed loop? I don't know how old the 02 is so I am going to replace it for good measures, but I don't want to just start throwing parts at this.