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Discussion Starter #1
http://www.youtube.com/watch?v=XjDqMFG7KiE

^Under a minute long video, tell me what you guys think^

Check engine light stays on due to "lean engine both banks" but smells too rich for that?

I'm leaning towards an oil pressure switch or something else electronic.

Vacuum, maf, iac, tps, spark plugs, wires, new pcm, and everything else seems just fine, anybody think they can take a stab at this?
 

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Most likely the codes and surging are due to that suspected leaking brake booster. Get that taken care of first and see if it helps/fixes this lean/surging condition first. Oil/filter brand/type/age?

How do you know the items you mentioned (MAF, TPS, IAC etc, no vacuum leaks) are in good order? Did you adjust the throttle body stop screw?
 

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Discussion Starter #3
Good thought once again on the brake booster.

As for the other items,

IAC, MAF Sensor, and TPS have all been replaced in the past six months, and have a good connection. I pull the IAC or MAF plug and the car seriously hesitates as well. The TPS can change the idle level if I had one screw in it (instead of 2) and adjusting it by twisting. Vacuum lines are all secured in place, and not dry rotted, I even tried spraying some cleaner on all of the lines to see if it would run any different. But there may very well be something I missed, lets hope it's the brake booster. Where do they usually leak at? If there is such a place
 

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Seems just fine is really not a good answer.

How long has it been doing this? According to your sig you've replaced everything.

I'll bring my code reader tomorrow and we'll check out the code(s).

How bout the fuel filter? Have you replaced that? Could be the fuel pump. Try changing the fuel filter and dropping a can of Seafoam in the gas tank. It may not solve the problem but it's a good idea to do those things anyway.
 

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Discussion Starter #5
Sorry about my answer, I guess what I meant to say was the items that "seemed fine" we're not suspect to me during my troubleshooting. The fuel filter was replaced last April, and I've always ran mid grade with the occasional seafoam (thru vac lines and fuel tank). The fuel pump is a possibility, I have not looked to it yet.
 

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Ok what I meant by that was that if you've replaced those items say so.

Something like "I've replaced all these things" or " "see my signature for everything that's been done recently ..."

Anyway, which plugs did you use? Brand is pretty important to these engines. Some plugs run great in these engines others are crap.

Also, have you checked and/or cleaned the MAF sensor? Sorry, I'm not too familiar with the '93 V6 engines.
 

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Discussion Starter #7
I have motorcraft double platinums, at .054, and I've cleaned the maf before without any real change, and I ended up replacing it as a preventative measure in March
 

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Ok, that's everything that I can possibly think of. I'm sure some others here with more motor knowledge will chime in. Wait until those night owls GM or Matt. Wake up I'm sure they'll have suggestions. :tongue:
 

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EGR Pressure Feedback Sensor

[QUOTE='93MN12]Under a minute long video, tell me what you guys think^[/QUOTE]


I've owned a variety of 3.8L Fords..Everything from Cougars,Sables, and Taurus's..

I experienced the same idle issues as you when my EGR Pressure Feedback Sensor failed..



I've seen the plastic melt where the tube meets the sensor, and the sensor also fail internally..

Sometimes the tube fails as well..If you replace the tube make sure to use quality emission specific style rubber tubing..So it doesn't collapse on itself, or melt.. :eek:

When the EGR Pressure Feedback Sensor, or the tubing attached to it fails..It will throw a check engine light, and you'll experience stalling, or idle issues..

These sensors are prone to fail with the high heat of the EGR gasses..

Adjusting the idle screw is just a temporary fix until you can replace the sensor, or tubing..Besides..It uses more fuel with the idle cranked up..

If your EGR Pressure Feedback Sensor has failed..Once you replace it..You can enjoy the better MPG..

I would usually take off the Negative battery cable for a half hour, or so after replacing the EGR Pressure Feedback Sensor..To reset the computer as well..




Rayo..
 

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Try this.

Unplug each and every vacuum line from the upper intake plenum except the for the one going to the fuel pressure regulator and cap them off. The EGR vacuum regulator, brake booster, EVAP canister and anything else you see coming off the intake (except the FPR). Reset the TPS so that the voltage is under 1 volt at idle. Disconnect the negative battery cable to clear the PCM KAM. Reconnect the cable after 2 minutes or so, then start it up.

If it runs fine, your issue is a vacuum leak. If it still runs like crap, chances are it's not a vacuum leak (but you still can't rule it out completely unless you test for leaks from the intake gaskets).

Something else you can do is the OBD self test. See this link for details...
http://oldfuelinjection.com/?p=13

As for the oil pressure gauge, did you do the pressure switch to sender conversion mod?
http://forums.tccoa.com/showpost.php?p=1320738&postcount=171
 

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Discussion Starter #11
I have not done that mod...yet. But I did just pick up a new dpfe sensor with some durable heat resistant hose, as the old one looks pretty ratty. I will take the neg battery cable off tonight and start it up in the morning with the new part and let you know
 

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A failed DPFE and hoses won't have any effect idle. It'll cause excessive flow at cruise or even a vacuum leak(when the valve is open). In the latter case though, the unmetered air potentially let in via the broken DPFE or hoses would simply be stopped in their tracks by the closed EGR valve. At idle, where the problem lies, the PCM is programmed to keep EGR off since load is so low.

Now if EGR were stuck ON though, due to a faulty valve or EVR, idle will be effected in similar ways to this. This scenario should give you a excess egr flow code. To determine if the valve or EVR is the culprit in this case, pull the green line off the EVR and check vacuum coming from it with a gauge or even touch(you can feel the suction). If there's none, it's good, the valve itself could be stuck open. If there's no EGR codes, it's probably something else.

I second Brandon's suggestion. Plug all vacuum sources and see if it runs better. If it does, reapply vacuum to components one by one to pinpoint the leak.
 

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Did anyone mention running codes? THat would be the first thing I would do. Takes a lot out of the guess work.
 

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[QUOTE='93MN12]I have not done that mod...yet. But I did just pick up a new dpfe sensor with some durable heat resistant hose, as the old one looks pretty ratty. I will take the neg battery cable off tonight and start it up in the morning with the new part and let you know[/QUOTE]

Any updates?..Have you tried the "brand new" dpfe sensor with durable heat resistant hose?




Rayo..
 

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Discussion Starter #15
Okay...I got the new dpfe sensor on, with a very heat resistant hose, and took the negative battery cable off for a few hours to reset everything. The dpfe code is gone, all that remains is the 172: o2 sensor showing lean on one side. Which could be due to a vacuum leak, I will try plugging them like he said. The car does seem to be smoother though. Still a little scared to turn down the idle
 
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