Lope at warm idle

[One-is-none]

Im posting for a friend, he has a 2000 7.3 F350, 140,000 miles, 4x4, zf6, straight pipe, cold air intake, no tunes or performance mods

His truck is starting fine, and running good, but once it warms up and idles, it has a faint lope. He had the injectors tested, all good, good fuel pressure, new fuel filter. Any ideas on what could be causing it? He says it sounded like a bad injector on the drivers side bank, but the injectors all buzz tested fine. Any ideas?

[roaddogjru]

Sounds a lot like an injector. Runs fine cold then gets rough when up to temp. The buzz test is only an indication that the injector is operable--not the actual condition. Get ahold of an AE analyzer and do a Cylinder Rotational Contribution test. With an AE analyzer, if a cylinder is indicating more than 3%, the injector is faulty. The three percent indicates that it takes that much more drive for that injector as compared to the average for the rest in order for that cylinder to "keep up".

If you use a Snap-on Analyzer it will just indicate "faulty injector". It will not give the values but thet are very accurate.

Also, flow bench testing may or may not find a problem that accurs only when at temp. They may all flow fine when at ambient temp.

Good luck