Ls IDLE bouncy (?) unless A/C is on....

[BlacksonAudio]

...THEN its sits about 8-900rpm. If I turn the AC off it goes up to 1000-1100 rpm then does that bounce thingy. The engine sounds like I'm casually tapping the gas when it does that. It threw 3 codes, 0171, 0174 and 0402... Any clue? I've read IAC, EGR, PCV elbow, tensioner, etc.... Like could this be more confusing than necessary.
Care to throw cheap to expensive, in that order?

 

[joegr]

You should put the year and engine in each thread asking for help.

 

[joegr]

Probably the PCV elbow and the EGR or DPFE.

 

[Robby D]

mine was doing that. 05 v8 i cleaned the k&n filter wich was filthy and oiled it. cleaned the trottlebody and butterfly valve. disconnected the battery hooked everything back up and its been fine ever since. idles at 600 after warmed up it would race or "bounce" usually wen coasting doing between 15 and 20 MPH. would fluctuate 200-300 rpm rapidly when my foot wasnt on the gas. very intermitent problem but what i did fixed it. hasnt done it since and its been about three months

 

[BlacksonAudio]

mine was doing that. 05 v8 i cleaned the k&n filter wich was filthy and oiled it. cleaned the trottlebody and butterfly valve. disconnected the battery hooked everything back up and its been fine ever since. idles at 600 after warmed up it would race or "bounce" usually wen coasting doing between 15 and 20 MPH. would fluctuate 200-300 rpm rapidly when my foot wasnt on the gas. very intermitent problem but what i did fixed it. hasnt done it since and its been about three months

Well, i cleaned the MAF the throttle, replaced the EGR (aftermarket/$45) and the codes disappeared for one day. Then they came back... argh. The same type of idling happens if it sits for 15 minutes. If i turn the AC on the idle is smooth and resides at 800rpm. I sprayed Carb cleaner near the valve and in the back by the elbow to see if there would be accelerated rpms but nothing happened?
Ive bought the elbow and valve but i hope i might have missed something so i don't have to take the engine apart.

 

[joegr]

So far, I don't know of any aftermarket EGR that has worked correctly (no check engine light) on the LS.

 

[BlacksonAudio]

You should put the year and engine in each thread asking for help.

Sorry about that joegr... I have a LS 2002 V6.. the 3.0 engine.

 

[BlacksonAudio]

So far, I don't know of any aftermarket EGR that has worked correctly (no check engine light) on the LS.

So you suggest getting a OEM/Motorcraft? Also someone suggested the DPFE sensor?

 

[joegr]

Yes, Motorcraft EGR. However, if you haven't replaced the DPFE yet, I'd do that first.

 

[BlacksonAudio]

Yes, Motorcraft EGR. However, if you haven't replaced the DPFE yet, I'd do that first.

You've been very helpful. Thank you... Can you point me in the right direction of the DPFE. I've found the part DPFE15 on Amazon for $64.xx but i cant locate it. Is there a engine diagram you know of? I guess Lincoln refused to give Haynes the right to make a manual?

 

[joegr]

... I guess Lincoln refused to give Haynes the right to make a manual?

That's not how it works at all. Ford/Lincoln had no say. It was up to Haynes if they wanted to invest in making a manual. They felt that there would not be enough demand (sales) to pay for what they would have to invest in making one, because there simply weren't enough LSes/T-birds/S-types sold. It's just as well, their manuals are not very good anyway.

I'm sorry, I don't know on the 1st gen. On the 2nd gen, the DPFE is integrated into the EGR valve assembly. Maybe on the fire wall?