I have a "94 FS Blazer with a 5.7 running $0D on a '6395. Problem is after PE enables it will not disengage until the throttle is returned to zero percent. I have driven over a mile with the WB getting richer until it hits 9.8:1 where it's bottomed out. This is at a steady cruise an a flat road.

I already have the extended PE at 1 second and stock was 50 seconds.

I have not seen this problem in quite a few searches here and on Google.

Thanks for any ideas or solutions.

There should be a TPS hyperstasis % to stay in PE. Basically it keeps it in PE until you drop 5-10% TPS below the entry value.

Sure its PE and not catalyst overheat protection you are seeing?

Thanks for the reply Fast. After reading it, I went thru every parameter dealing with PE, did a parameter search for "hysteresis", checking all listed items for a connection or change from the oem bin.

The cat overheat items would imply that there is some way for the ecm to know or infer that that the cat is too hot. My truck has shortie headers with the stock o2 sensor location in the y-pipe just before the cat, how would the ecm know either way?

This weekend I'm going to paste my ve and spark maps to the oem bin and see if anything changes.

Just today trying some things on my way to work I was easily able to get pe to run for 20 seconds, partially downhill, at tps as low as 11%.

Again thanks for the reply and ideas on where to look.