Shaking and hasitating

[myz06Exped]

Hello, you guys ...I need some help here.....I have 2003 ford expedition 5.4L ...110,000 miles.....the problem started out of no whare it starded to shake usually around 1,500rpms when its in higher rpms its fine, No check engene light...new fuel filter , new air filter (Maf cleaned and also preformed the vac system flush with a seafoam), new plugs, new COPs, new intake Air temp sensor...also I removed and cleaned the idile control part...still the problem is there . The car starts fine no isues when its cold and at first seems like its idiles good too then when it warms up u can notice that the engine shakes, to the point that u can feel it when u sit in the car, and when I put into the Drive position without touching the gas pedal the car starts to roll and jerk...so what is going on here Im about to give up?..do I have a vacum leak ? i checked most of the houses i didnt find anything ...how can i check for vacum leaks better?

 

[jdecker]

Does the service engine light come on when you first start it (i.e. go from key off to run)? If it does have a scan done to see if you have any pending codes

 

[EXPI2000]

U can spray wd-40 along your vacuum lines and if your engine revs at anytime then u have a vacuum leak at that point...just make sure u arent soaking it in it lol

 

[myz06Exped]

no I dont get service engine light and no pending codes ...i only remember one time one came up it was probably in a history or because when i unpluged the IAT sensor while the car was running it came up on the scaner tha IAT sensor and lean code bank 2...I replaced the IAT sensor after that and deleted the codes ... buddy of mine just got a nice real scaner (not the hand held one) so will check it out tommorow

 

[myz06Exped]

Ill spray the WD40 tommorow too will see what happens..where do I spray exactly ? I think I sprayed the seafoam through one of the lines that hooked up above brake drum

 

[Spooky]

Could you have a bad COP? Sometimes they misbehave at odd times.....

 

[EXPI2000]

Just spray along all vacuum lines and if u have a hole in a line it will suck in the wd-40 and idle will jump up

 

[metaldrgn]

I believe there is a TSB out about the egr valve causing that kind of issue.

 

[wcm7823]

My #1 cop went out and it shuddered in overdrive 2000rpm...replaced and it was OK... No check engine light

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[myz06Exped]

so I tried the WD40 trick and no luck i chacked all the vac lines visualy and no luck ....im missing something there....U guys think its EGR ? ...also I forgot to mention in the begining, at the end of the tail pipe when the truck is hot, the exhoust gas somehow comes out not in a steady stream but somewhat with an intervals I also did a dollar trick (I held it at the end of the pipe) and it was flapping it around and sucking it in back and foth into the tail pipe....its wierd I know..what can this be?