Rough idle with check engine light - PowerStrokeNation : Ford Powerstroke Diesel Forum
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post #1 of 2 (permalink) Old 03-12-2019, 02:06 AM Thread Starter
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Rough idle with check engine light

Hey guys.. I’m in a bit of a concern here. I’d like to ask you guys on what to do with my 97 Ford F-250 powerstroke. So this truck has a good 360,000 miles on it, and was used a lot for work and all that, but on start up, about 10 seconds in, it’ll go into a baaaad idle, with the check engine light on. Now I put a new fuel filter Inline in it, and cleaned the return line, put new batteries in it, and that’s it. The idling returns to normal after being ran for a another good 10 seconds. If you guys have any idea what’s going on with my truck, that would mean a lot. Yes, there are some compression issues and that, and there is some blow by because of wear and tear, but it always ran so perfectly, even with that.
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post #2 of 2 (permalink) Old 03-13-2019, 01:01 AM
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Location: Tehachapi, CA
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Re: Rough idle with check engine light

Without knowing what code was thrown, I would check all the external connections to the valvecovers (2 per side) for evidence of melting or burning. There should also not be oil in the connections seeping through the area of the pins in the gasket. Remove the oil cap and sniff it. If it smells like burned electrical insulation you probably have burned under valvecover harness(es) (UVCHs).

For checking the injector/glowplug wiring: From each valvecover gasket connection's outermost pins (2 per connector) to ground you should get 0.1 to 2 ohms (indicates good plug and wiring). From each valvecover gasket connection's center pin to each immediately adjacent pin, you should get around 3 ohms (indicates good injector solenoid and wiring). You should not get any continuity from any of the outer pins to the 3 inner pins (indicates no shorts between injector and glowplug wiring). You should also get 0 to 1 ohms from each of the external harness connectors outer pins back to the Glowplug Relay's large terminal on the GP side (indicates good wiring from external connections back to the relay).

Also you might want to remove the Injector Driver Module (IDM, silver box below the drivers hood hinge) and see if there might be water sloshing inside. Cheers!

97 F250 SC 4x4, E4OD, 4.10 LS, Basically Stock, Relocated Block Heater Plug, Ext Trans Filter, Tru-Cool Max, I/C Mounted but not Plumbed

SOLD: 94 F350 CC DRW PSD, 5 Speed, 4.10 LS, SBC Con-O, Baldwin Filter, Tymar HPX Hose, 3” DP, Bilsteins, $12 AIC, Coolant Filter, Explorer O/H Console, Trans Temp, Boost, and Pyro, Pedestal Mod, Gutted EBPV
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