I have a '96 7.3. Bought it with 170,000 miles it now has 220,000 miles. It has always had a rough & low idle (525 RPM) when hot. Truck runs great before it warms up. The hotter the engine temp the worse it runs. Finally got tired of smelling the fumes and took it to Ford. They have told me # 7 injector is bad and the others are weak. Could that be right or could something else be wrong? Why does it run smooth before its hot? Any information would be appreciated.
Thanks,
John

 

I bet you the rough idle problem is a simple IPR o-ring leak. But with 220,000 miles your injectors may be getting a little tired. I have been told at on average ~150,000 miles they need rebuilt. I replaced my original injectors with 250,000 miles on them with some new ones, but they were still working fine.

 

What is a IPR o-ring and where would that be?
Thanks for the information.

John

 

Foremans's right (usually is) IPR orings will cause those symtoms.

Not to hard to do:

http://cw-diesel.com/LuxSite/IPRInfo.htm