I put a another tbi 350 engine in, was running great for two weeks now starts surging

[Tyree]

I dropped this engine in truck and was running fine for about two weeks. I then washed my truck then started it the next day and now it starts to surge at idle up at down. I previously had a surging problem caused by my previous map sensor being wired up incorrectly. I worked all those bugs out and this engine was going great till after I washed the truck. I cannot detect any vacuum leaks from any of the known sources of vacuum. Anbody have any ideas on this.? TPS, IAC, MAP, fuel pump Etc.. all working correctly. I m suspecting something got wet, some wire, somewhere but I could be biased because of previous problems so don't want to say that is the cause just a thought. I attached a log. An help on this would be appreciated.
Thanks Tyree

[damanx]

I'm throwing a guess here, but looking at the log, I don't see the o2 sensor doing anything other than being stuck at about 440mv.

[Tyree]

Thank for the reply damax, does anybody know what is an expected proper reading from a one wire o2 sensor at idle.? I will check this today.
Thanks Tyree

[Tyree]

Does any body have a .xdl log file of a known good running 5.7 so that I may compare my values in my log against a known good running engine.? That would be a great help. Thanks to all in the forums

[Tyree]

I just swapped another o2 sensor. Same result. Any other ideas out there?

[damanx]

here is a log I made a while back. If you select the monitor function during the playback, you can see the o2 sensor swing "high" and "low"