99 2.5L Automatic tranny w/70K. I have often felt a little hesitation at idle just when I start to give it gas. Also at idle (right around 1K rpms), in drive, it will 'surge' rhythmically such as...(yes this is my best description) rrrrr......rrrrr.....rrrrr.....rrrrrr. No odd noises just surges ahead in that manner. No other issues with it at any other rpm or speed.

Have done plugs, wires, fuel filter, cleaned MAF sensor.

 

sounds like you might have a lot of carbon build up in your motor...try cleaning the throttle body and getting some seafoam to run through the motor....that should help some....it also could be an IAC going bad

 

Finally gave me a CEL yesterday while I was driving. Stopped by local auto parts store to have the code checked and it is ' EGR flow insufficient'.

Got it home and unplugged the single wire to the EGR valve(?? I think) disconnected the battery to reset the CEL and driving it now, seems ok....

 

I would suggest cleaning out your EGR. They have a tendency to get gummed up and the valve is not able to move freely. That can cause the insufficient flow. I just don't see how clearing the code will solve the problem?

 

I left the EGR disconnected. Maybe it is malfunctioning or maybe, as you said, it is just gummed up.

 

CEL is back....

 

I tried removing and cleaning the EGR valve. Ran ok for 20 minutes or so and then CEL came back and hesitation resumed.

SOOO....after some more research I think I maybe getting closer to an accurate diagnosis and remedy. I'm leaning towards the DPFE sensor being bad.

If it is bad and sensing that there is little flow through the EGR tube, then it would be telling the PCM to open the EGR valve more, causing a leaner mixture and the poor running condition I am experiencing, AND the reason it runs better when the EGR valve vacuum tube is disconnected.

Sound sensible??

 

^^^Uhmmmm ok?

*i don't have a clue but keep us updated. i like it when someone figures it out...plus it gives me something to look at on my truck.

 

Will do. So I just disconnected the vacuum tube the the EGR valve and plugged it with a screw so it wouldn't be simulating a vacuum leak. Will see what happens. If it seems to run better, I'm going to replace the DPFE (or pressure feedback sensor as I think Ford calls it). I will keep my results posted. BTW--does anyone have any experience with fordoemparts.net or any other online source for OEM Ford parts?? The local Ford garage wants $140 and at fordoemparts.net I can get it for $72. I want a Ford part as I've read aftermarket sensors aren't quit up to par. Thanks!!

 

Update....with vacuum tube to EGR valve disconnected and plugged, it runs MUCH better. So....I am going to order a new pressure feedback sensor and see if that rectifies my problem and my CEL.

 

DPFE sensor replaced and no check engine light (x2 days), but it still has a little hesitation at idle speeds.

 

So here's the update. No check engine light, so the feedback sensor definately cured that. But since I reconnected the EGR valve there is still a slight surging at idle speeds. Not sure what is going on. It seems when I had the EGR valve disconnected there was no surging, but now with new DPFE sensor and EGR reconnected, the surging is back.....hmmmm Any ideas?????????

 

01 2.3 auto 203K miles. I also have a surging idle and terrible gas mileage, but no CEL. Following this forum to see if you guys have tracked it down...