P0340/Surging / Help

[crazymoon]

i have been reading alot of webpost, manuals, and now i need help. my ford windstar(1998 3.8, 110,000 miles) has the CEL P0340, the van had the usual surging, no power while accelerating and bucking. Now ive gone thru alot of part changing, VSS, IAC, MAF, IMRC's, tackled every problem that occured myself. but this one takes the cake, when i first got P0340, i replaced the sensor, didnt look bad but changed it anyway. the van still ran rough, changed fuel filters, added additives to the fuel, fule cleaners, etc. still the same problem, i finally got the camshaft sensor alignment kit in and checked it and the synchronizer was aligned. Before this P0340 occured i had changed the sparkplugs and wire set, i looked at the coil pack and it was fine. the surging and bucking occured about 5 days after the change out. i have looked at the wires and coil pack again and it looks still fine. i am now leaning at replacing the camshaft synchronizer(150.00) at ford. does anyone have any other suggestions before tackiling this problem, i have read post about EGR but im at noob when it comes to that

[12Ounce]

Breaks in harness wiring can be daunting ... especially if they cause intermittent problems... but that's my guess. Sometimes the problem is in the connector itself... sometimes a conductor rubbing on a metal surface. ???

If you can attempt to rotate the top of the synchronizer and you feel no looseness...or you haven't heard any noises coming from the sychronizer... I would guess it's not the problem. But you may have to replace it just to eliminate the possibility.

[crazymoon]

i have heard some squeaking in the past but it was always the small idler pulley in the back, alot of WD-40 would do the trick but it always comes back now and then. any tip on testing wires other than pulling them off and looking at them?

[12Ounce]

I'm the worse guy to ask for tips on the subject.

I once ended up taking my whole drive train harness out of the engine box (took me about a whole day), to find a problem I should have seen straight-away.

So, I guess I do have a tip: Don't do what I did!

[crazymoon]

any takers?

[crazymoon]

after further investigation(reading), i disconnected the DPFE and ran the vehicle and it ran fine, i purchased a new one and will install tomorrow. Funny how orileys had no part named DPFE but rather id as an EGR.

[wiswind]

DPFE = EGR flow sensor. Strange that it did not light the CEL. The DPFE is a common failure item.

You might also squirt a SMALL amount of "Seafoam" into the vaccum hose that goes to the top of the EGR valve. This is to clean / lubricate the EGR vaccum solonoid, which is located on the back of the upper intake manifold.

[DRW1000]

The new redesigned version of the DPFE should be black plastic (Motorcraft) as the alluminum one is failure prone

[crazymoon]

the item i bought was oem made by Barq i believe and it was the aluminum case not black, can i assume that this one will fail in about another 100,000 miles. When you say use sea foam on the egr, i see only 1 vacuum line on top of the egr valve.

[crazymoon]

i am going to bump this because i really need help. after i changed out the DPFE the van ran fine(3 days). Today i took it out on a 45 mile drive and the CEL came back on and the van jerked and hesitated. i did the seafoam thing, and even put some injector cleaner. i took it to autozone to where as no surprise the only code given was P0340. the tech told me it could be the wiring or the timing belt. i dont know how to test the wiring, much less the timing. any experts out there who have tackled this problem past the sensor as that was replaced a month ago.

[12Ounce]

You may want to bite the bullet and buy a wiring diagram for your model. Then you can do a pin-to-pin harness continuity check between the cam shaft sensor connector and the PCM ... and all connectors inbetween, if any.
Usually around $35 from helminc.com

[crazymoon]

as an update to this dilema, my CEL went away but i have noticed on occassions when slowing down the RPMs will rev up or not downshift, kind of like on a stick at high speeds and you shift to a lower gear you get the rev. thats whats happening now. am i looking at a transmission problem now. this has only happened 3 times after i put some seafoam into the egr vacuum line. i figured the egr got cleaned so its acting better now. can i put seafoam into the transmission fluid? also i am still getting crappy gas mileage. anybody solve the gas issue?

[wiswind]

The Seafoam into the vaccum line on the top of the EGR valve was to clean / lubricate the EGR vaccum regulator solonoid. It ends up going into the intake manifold...and being burned in the engine.

The Seafoam can does say that it can be put into the transmission fluid. I would not do it.... I would just change the tranny fluid and filter.
I believe that your '98 will use MERCON V fluid.
The tranny fluid MUST be changed at least every 30K miles....21K miles for "severe service".
Many of us...myself included invested in a tranny or rebuild at around 100K miles....but I would not jump right to that $$$ conclusion right off.

If the idle is acting strange....you might look into the Idle Air Control (IAC). This sits on top of the Upper intake manifold....next to the throttle body.
They are known to stick....many have cleaned/lubricated them with something...such as a bit of Seafoam spray. The IAC is held in place by 2 bolts....and you would spray the cleaner inside it.
The IAC controls the air going into the engine when your foot is not on the accelerator. The computer controls the idle speed by opening and closing the IAC. FORD says not to clean the IAC, but to replace it. I have sinned.....and cleaned mine......

Gas mileage can be pretty bad in the cold winter months.

Also, when your CEL was lit, I would expect that your mileage would be lower. And...if your EGR was not operating / or operating incorrectly.....that would lower your fuel economy also.

If you reset the CEL.....it will take the computer a little while to "relearn" the driving information.
Shift points are a part of the data that it needs to relearn. However, it should not take a lot of driving to relearn the information......

[crazymoon]

Wiswind thanks for the reply. where to start, i have gone thru a barage of parts changing. first it was 1 IMRC, then came the IAC, MAF, VSS(that was hard), PVC, vacuum lines, Plugs and wires, camshaft position sensor, and lastly the DPFE. i did a transmission fluid change about 2000 miles ago(small town). When i say the CEL(P0340) was on, it came on 3 days after i had replaced the DPFE. after that is when i added the seafoam. 1 day after the seafoam and driving about 5 miles the light went out. then the downshifting problem began. it hasnt happened for about 2 days now but i feel little kicks in the engine when it shifts. no CEL has come back on. As far as winter, i live in south-east Texas, though it did snow here for a day(24Dec) the weather had been in the 60-70. i have not taken the injectors out just added lots of fuel injector cleaner should i take them out and if so what will i be looking for? and to add more injury the stupid dome light is now a problem, i have done what every body recommends, sometimes it works sometimes it doesent, kind of hit and miss, i have narrowed it to the passenger front door. i havent tackled the CPSync, even though some sites say to look at it. i do have the alignment tool, but it looks pretty hard to get to.