1997 Expedition w/ 5.4 Need help

[mw1957]

My bulletproof non leaking 1997 may have taken one for the team. Last she ran good, according to the wife, there was what felt like a "flat spot" sometimes up around 50mph. Take your foot off and get back on it and she as fine. But eventually did it again. Finally the ol girl just kinda quit. So I have a friend scope her and he tells me it's the EGR valve. So this weekend I yanked that and replaced. She runs. But not good. Runs very rough at low rpms. Sitting in the drive, I can't keep her at 1000 or even 1500 rpms. But no problem keeping her at 2500 or even 3000.
So what else should I be looking for here? Thanks in advance

 

[designit]

Welcome aboard.. IAC (idle air controler) / throttle body-manf. would be where I'd clean up first I suppose...

any other codes / other issues?

 

[mw1957]

Thanks. Will look that up and get that done. No other codes now. The guy that read them first then disconnected my battery (which has since died) and I have no CEL now. No codes.
The only other symptom is she sounds a little "throaty" which may be a cat and unrelated. But I am a rank amateur at this and I'm just diving in to see if I can get her back on the road. Thanks for the help and the welcome.

 

[designit]

I was talking about just 'cleaning' not to change (at this point) to clear that up... remove the IAC & blast it inside with throttle body cleaner... Check your air filter & remove the tube off the intake manifold & shoot the flapper with TB cleaner all over, wipe out as much as you can & see if that helps (short term)... You could remove the TB & clean it right, later... You may want to bleed the fuel pressure off?? And you may even want to try some Seafoam (down the brake booster hose - method)... there's a recent thread on seafoam roaming around here somewhere... Good luck... (I wouldn't go to cops or plugs just yet.)

There will be suggestions from others...

 

[mw1957]

Yes, I meant cleaning too. Less buying the better right now.

 

[designit]

Yeah, I figured you knew... Just that "I" was a little wishy-washy in my reply...

 

[mw1957]

How do I disconnect the electrical connector to the IAC valve on this thing?
I have the IAC Valve off ( a real bear under the firewall like that) and it comes part of the way out. The electrical connector did not come off easily but more likely I can't figure it out. How does this thing release?

 

[designit]

pinch the outer housing and pull off.. (may need to wiggle it slightly?)

You should feel the lever give a little when you grab / pinch it...

 

[mw1957]

Got it. I couldn't see it well enough and was squeezing it wrong. Got it out, got it off and got it cleaned. Put it back on. I can actually hold it at idle now around 1500 rpm and it stays. But still sluggish/missing at low rpm at acceleration. I have not cleaned the MAP yet. But now where? What does she sound like now? Better, but still not there. Thanks for sticking with me on this.

 

[mw1957]

Ok. I have done everything here except the Throttle body. Runs better, but not good. Low rpms really rough. Once (sitting still) I get it up to about 2000 rpms she smooths out and I can hold her there (or higher) but won't hold well at 1500 or below. Drove her down the street and can't get her up to high enough rpm to run smooth. Rough. Better than before, but something still wrong. Thoughts?