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Discussion Starter · #1 ·
Hey whats up!

Here's whats goin on:

I have a 2002 Taurus SES 3.0 DOHC Duratec

I recently did a tune up with the following items:

NGK V-Power Plugs
Autolite Plug Wires
Replaced Coil Pack (mine had 4 noticeable cracks)
Replaced PCV Hose
Replaced Fuel Filter
Cleaned MAF
Ran Seafoam through all recommended systems

Thing is that the car ran decent before all this (for a 140,000 highway mi car.) What's happening now is I have a miss. Usually at partial throttle (like tryin to go up hill or passing.) When I'm at a stop it also will "stumble."

I have checked and rechecked correct coil pack order/firing order.

Disconnected the MAF (car dies.)

Checked for vacuum leaks (none)

Disconnected TPS (car stumbles)

Only code showin up is misfire cyl. 2 (so I did a comp. test...210psi across all 6 cyl.)

My brain is fried on what the heck it is...maybe NGK's? Dunno? EGR? o2's?

P.S.- Stumble is really prominent when car is warmed up after like a highway travel.
 

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If it ran fine before, swap plugs and wires between #2 and another, see if the miss follows.
 

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Had a similar problem on my then new 99 Ranger & found a cracked #6 plug insulator with a "wet down" test.

So you might try a wet down test on #2 plug & wire, with a spray bottle of water. If done at night look for arcs & sparks, or idle stumble.

If no joy, pull the #2 plug & check it's intenal insulator for cracks, or chips.

Still no joy, pull the #2 plug wire & check it's end to end resistance while wiggeling, it should be steady & about 1K ohm/inch of length, 30K ohms max.

Let us know what you find.
 

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OK good feedback, did you do the end to end continuity test on the #2 plug wire????
 

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Try the old coil pack.
 

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Discussion Starter · #8 ·
Ohms are spot on and the old coil was shot. Could a clogged EGR be to blame? As i stated i ran seafoam through system not sure if maybe it knocked some stuff loose and clogged up.
 

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OK, more good feedback, so lets think about this some more.

You didn't have the miss before you did the tune up.

On the tuneup you replaced the plugs, wires & coilpack, PCV hose, cleaned the MAF sensor & dosed things in some way with Seafoam, we're not clear on what, or how you did this treatment.

Now you have a code for #2 cyl misfire.

You've done a compression check, wetdown & end to end resistance check on the new #2 plug wire, replaced the new #2 spark plug with another new one & still have a #2 cyl misfire, thats intermittently present at idle, but Worse when the engine is Loaded.

SO, it seems to me, the only two things not checked so far, is the #2 fuel injector & the new coilpack. Just because it's new doesn't automatically earn it a pass, even if you bench tested it, it could have a high temp breakdown problem!!!!

The #2 fuel injector may have been messed with by the Seafoam dosing loosing up but not removing deposits, but right now we don't know how you did that treatment, so we don't know if the Seafoam may be suspect.

If you didn't have the new coilpack bench tested for output, or at least had them test/ohm out, the secondary windings, before leaving the store with it, then it belongs on the suspect for now.

The miss under load & intermittent miss at idle, sure sounds like a spark problem.

BUT I suppose we can't rule out the #2 fuel injector, or maybe even CCDF (Combustion Chamber Deposit Flaking), causing a momentary valve sealing problem, by the Seafoam loosening up & cleaning/removing combustion chamber deposits & having them stick on the exhaust valve seat & cause it not to close & seal good, until it's blown away.

So if you suspect CCDF may be the case, take the vehicle out for Fords high rpm blow it out portion of their Decarbon proceedure, by giving it a good hard high rpm run for three miles at rpm's above 3600 & see if that'll help. If it does, then you'll know it's a CCDI problem.

If no joy, then maybe listen to #2 fuel injector, to determine if you can hear a difference between it & the others.

If still no joy, if you haven't already done so, do the ohms check on the coilpacks #2 secondary winding with your multimeter. It should be 13-15K ohms.
OR, if your, or another store, can bench test it, pull the coilpack & have that done, paying close attention to the #2 voltage output. Maybe even take a hair dryer along to heat that puppy good before or during the test, to simulate it being at temp on a warmed up engine when the misfire occurs.

A bunch more thoughts for consideration, let us know how it goes.
 

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Discussion Starter · #10 ·
I believe i may have tracked down the issue at hand...I have been tinkering with the DPFE sensor to see how things run. Is there a specific cyl. that this unit refererences from? Possibly cyl. 2, as it sits right behind it.
 

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DPFE doesnt measure anything from one particular cyl. It measures EGR flow thru EGR valve based on pressure differential across an orifice. EGR flow comes from the rear bank exhaust manifold (bank 1) via the tube that goes to the EGR valve.
 
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