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

[damanx]

I just ran your log again and about time 4:29, you get a Code 34 "Map Low" error. Maybe something going on with the connector or the map sensor?

[Tyree]

on that map thing, That was me disconnecting the map sensor for a minute looking around for problems. Thanks for the reply I will check and compare. Phantom problem is repeatable and went from running great to running like crap. Thanks again

[Tyree]

Thanks for that log. Does anybody have a log of good running 5.7 from start in open loop until it warms up to idle and closed loop. This is when it starts happening in my truck as soon as it goes to closed loop, it surges small up and down and then idles like crap till it dies. Thanks again to all

[Tyree]

I decided to swap out egr valve with another one I had laying around. I ran the engine again and it ran much better. I will have to test drive and keep doing more logs. I revved this one up a few times during log. Does anybody know what normal idle rpm's are for a 1990 5.7? I attached the log so if anybody can watch it and let me know if they see anything strange. But it seemed to be running better.

[damanx]

I always forget the egr valve. I'm not running one.