This is my first post on this forum. 1997 F250HD 7.3l turbo diesel power stroke 135,000 miles. 2nd time with last month this issue has occured. Driving along no real issues, then suddenly engine starts making a very loud locking noise, will lose power and then quit. Seems like a fuel issue. Switching tanks is of no avail, but then truck wont start, it turns over, making loud knocking noise but no start, about 15-20 minutes later it starts, at first it is very rough but within a minute or two it smooths out then truck runs as if no issues, I have noticed the mileage seems to be decreasing. Last time this happened it ran for almost 2000 miles then early today same issue returned, got it back to house (towed) to start troubleshooting and it started first very rough no power then suddenly it is running fine no issue, have put 50 miles on it since last incident, any ideas? Would CPS cause this, would failing mechanical fuel pump be a probable cause, just not sure how to chase this one.