ROUGH IDLE WHEN IN GEAR??

[Mr Mick]

So I changed out the intake manifold and I think I put everything back where it is supposed to be. My short term memory is shot. So the top lines might be wrong. Can someone look at these pics and see if they are on right.
2004 Ford Expedition, Eddie Bauer.

 

[whtbronco]

I'm struggling to follow the hoses, but I don't see any glaring issues with the routing. Any codes? Fuel pressure checked?

 

[Mr Mick]

No check engine lights, fuel pressure seems fine. There was no problems till I changed out the intake manifold.

 

[whtbronco]

If it's running rough we can hope there are some codes. They don't all trigger the CEL and in some cases it takes a couple cycles of a code being seen before it will trigger the CEL.

The intake manifold as you are well aware requires removing and disconnecting quite a bit. You might consider getting ForScan and an OBDII adapter so you can read codes and do diagnostic testing. Things like air, fuel and fire can be looked at from the data available in ForScan.

Short of that all I can suggest is to go over everything to ensure it's connected. Though I kinda figure you already have, maybe more than once.

 

[99WhiteC5Coupe]

No check engine lights, fuel pressure seems fine. There was no problems till I changed out the intake manifold.

Did you disconnect the battery during the work?

Have you inspected the inside of the throttle body bore? Is is dirty?

Over time, the car’s computer will compensate for the reduced airflow as the inside of the throttle body bore and butterfly valve get dirty (and let less air bypass the blade at idle).

If you disconnect the battery, the car’s computer resets to its original programmed idle - assuming the throttle body bore and blade is clean. If it is dirty, it can cause a rough idle as there is not sufficient airflow in the throttle body at idle.

Cleaning the inside of the throttle body bore may improve the idle smoothness for you.

 

[JerryT]

Wait for codes, they will come. In the mean time I would remove and clean your idle air valve (two bolts and 1 electrical connector) and replace your PCV grommet on the valve cover. They’re two culprits for rough idle, then wait for it to throw a code(s).

 

[Olpap]

Try disconnecting the vacuum tube connection from the EGR valve and see if it smooths out. I have been having problems with my EGR controller lately and it smooths out when disconnected. You will get a code eventually but the engine should run just fine. Mine does. Just looking at the overall system it makes me wonder why aren’t both cylinder banks tied together if it’s supposed to recover some of the exhaust gases.