2000 expy, 5.4, 100k miles, orig owner, garage kept.

good maintenance schedule and no major problem history.

i had the plugs replaced last winter at 90k miles. after the plug change i started noticing a rough idle when the weather was cold (temps below 35 degrees).

i dont notice the rough idle upon initial startup but after i drive a few blocks and stop for a light my engine really starts to idle rough.

i can see the tach jumping a few hundred rpms (usually lower) and the engine actually runs rough/ vehicle shakes a little. it feels like the engine might stall but never does. no cel.

when i take off from the stop, the engine seems fine with good power. it might do it at the next light, other times not.

this is the second winter that this is happening. the entire spring/summer/fall there were no problems. now that the cold weather has started again so has my problem. this is related to the cold weather.

after the plug change last year, the shop said they cannot find anything wrong. i called them this year and they said there is nothing they can do.

does anyone have any ideas what might cause this? there are no CELs or other lights. fuel filter, pcv, air filter all have been changed.

thanks!

 

Can't help you, except to say that mine does the exact same thing. So I'll be watching with you as the experts weigh in on this.

 

Did you clean or replace the IAC valve yet?
Did you check the PCV hose at the rear of the engine for cracks?
The EGR passageways could be mostly blocked with carbon build-up.

 

thanks for the reply alloro.

i will check these out.

 

All I can say is read this thread from front to back. It saved me sooo much $$ and frustration!!!

Here's the link.......
https://www.ford-trucks.com/forums/8...174-codes.html

I was going nuts trying to diagnose the same sounding problem, and that damn little elbow on the vacuum assembly was what was causing all my problems.

 

Hey Guys, I am reseaching the same problem and I am finding this TSB # 05-4-17 sounds like it could be the culprit. I am just starting the research... Mine does seem like a nice vacuum (EGR open) leak. I will check back and post if I do any research soon.
05-4-17***INTERMITTENT ROUGH IDLE - NON-COMMANDED EGR FLOW

chris

 

I did these things here and cleaned plenum, replaced EGR and put back together. Runs great.... until problem came back. Mine clears up after 10-15 minutes. I did not do anything with the IAC except remove and clean port, not valve. I will try that today. Still searching....

 

I had a like problem, when coming to a stop the RPM would dip and idle a little rough. Changed IAC, but that wasn't it. Want to say that the reason mine would show up in colder weather, is that's when I had the AC off, so the idle wasn't pushed up for other reasons, thus the rough idle was only with AC -Off.

Haven't chased it much more, ie the hints above yet.

Thanks

Mike

 

I have the same problem on a 2000 Exp. I have chased this gremlin for 3 winters. I have checked the PCV vacuum lines, Changed the EGR valve and MAF sensor. There is a simple fix for this I just have not found it yet.

 

wondering if anyone has figured anything out on this thread yet? My expy does this too but only in the winter...all other seasons she runs like a champ. I havent replaced anything but i dont wanna play the elimination game....im too broke for that. Any help?