2000 7.3 works when check engine light on, not when off
First of all congrats for this great forum.
I just bought a 2000 7.3 turbo diesel crew cab lariat, when i bought it it came with the service engine light on, I drove it for 5-6 days on the city without experiencing any problems, I took it to the road and after a 40-50 miles the light went off, when I stopped it started with a rough idle, tach needle moving crazy, turn it off, then started again without any problem and the check engine light was on again, that happen during my 800 mile trip like 3-6 times sporadically the problem went away just by pressing the gas pedal BTW.
Then on my way back things change, when I was on the freeway at around 60-75 MPH it started to fail as if it were on bad timing or something, but never lost power or anything, thats when I noticed that the light went off, I reduced speed and around 60 mph the light turned on again and everything felt correctly, that happen again during the trip 8-10 times, everytime the light went off the engine failed on high rpm until the light came on, the last four hours of the trip the light never went off again and the truck just worked perfectly.
BTW I stopped at an AutoZone and they couldnt get the codes.
Sorry for the long story and for my very bad english, of course zero diesel experience.
Hope anyone can give an advice. Thanks.