Eagles International Forum

Hi guys,

I have a puzzling (to me) problem with my 1989 6v92T that began about 6 weeks ago. It follows the same pattern each time. Engine starts fine and runs great/normal for about 15-20 minutes. Then the engine loses power and seems to “miss” somewhat. Speed decreases to 25-30. Will not go faster no matter what I try. This period lasts for about 10 minutes. Then the engine seems to resolve the problem and bus slowly picks up speed to normal and thereafter runs fine for remainder of trip. Next day, pattern repeats. Thoughts?

Steve

Automatic or manual?

If automatic, DO NOT TRY THIS!!!

If manual, next time this happens and it is safe to do this (at least 50 MPH on an open flat straight road in highest gear plus little traffic), put gearbox in NEUTRAL. Release the clutch and turn engine off but leave ignition on. Let it coast for at least 15 seconds and restart engine. Coast at idle for at least ten more seconds and put her in gear.

If nothing changed, you have most likely an electronic problem somewhere, like in the engine management computer or a sensor sending bad info to the computer. Oil pressure and coolant temperature sensors are good places to start looking but don't forget things like the throttle position sensor and the mass airflow sensor.. Understand this is NOT a cure and does not normally solve the problem that causes this behavior. It's just a way to make your driving easier until you get the problem resolved.

If automatic, is it a DDEC (electronic) engine and gearbox? It may be going into a 'limp mode' for awhile, likely for a bad sensor as above.

In both cases, replacing the bad sensor or computer will likely solve the problem. Worse yet, it may expose other elcetronic problems.


Good Luck!!!

Thanks! It is an automatic. A sensor issue of some type is a good place to start. Appreciate your thoughts and time!

That is a 748 in NJ Transit if you suspect a limp mode just pull over and turn the switch off and it will clear the limp mode but check your fluid

Thanks for reply. How & where would I turn off switch?

Master switch...shut engine off and restart

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Roger!