5.9, 300hpisb, intermittant fast idle

[Stormalong]

Just bought this new to us 2003 Journey DL with 300HP Cummins isb. We have driven it nearly 2000 miles, but in the last 300 miles we have experienced occasional fast idle upon warm engine restart. Always works fine cold, but occasionally when shut off for a few minutes like to refuel, it will idle at 900 - 950 RPM. The Allison transmission will not allow shift at this fast idle speed. I have had to shut off, restart, 2 or 3 times, then it idles OK. Any clues? Stormalong

[MartinP]

Depending on the model a fast idle can be obtained for warm up using the cruise control or a fast/slow idle switch that may be placed on the dash. Either way the idle is controlled electronically. I would give Cummins tech support a call. It may well be just a dirty connector in the engine bay. You could try reseating the engine ECM and injector electrical plugs if you feel comfortable doing this kind of work.

Martin