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Discussion Starter #1 (Edited)
I have a 2002 se with the vulcan going on 185,000 miles. I pulled codes for a misfire in the #1 and #5 cylinders and misfire on startup. The car runs beautifully when on the freeway with no change in gas consumption. When stopped or idiling the car shakes a bit, and cel blinks sometimes, however upon acceleration or increase in RPMs everything is normal.

I've changed the plugs, wires, and coil pack but aside from better gas mileage it hasn't stopped the shakes or cel when stopped. I'm at a loss as to what's next aside from looking into new injectors or fuel filters.

Any suggestions would be helpful, and I do have a miltimeter at my disposal for testing whatever.

Thanks!

BTW I've also replaced the PCV and PCV elbow and checked for vacuum leaks with starting fluid
 

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we're not much use to you without having the codes. any major parts store should be able to do this for free. sounds like IAC or vacuum leak but we're like you, just guessing..
 

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Flashing CEL = missfire bad enough to damage the cats = BIG $$$ spent replacing cats if you keep driving it with the missfire.
 

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What parts did you use for replacement would also be my question.
 

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Discussion Starter #5
P0301 - Cylinder #1 misfire, P0305 - cylinder #5 misfire and P0316 - misfire in first 1000 revolutions. Pretty much exactly what i said in my opening post but... you asked.

Interestingly enough I don't know if my cel lamp burnt out but it was off this morning and hasn't came back on. Never ever in my experience have I had a dummy light turn itself off or the car correct the problem itself without help.

Motorcraft coil pack, and wires, autolight plugs. All new OE parts.
 

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I just had 0340 code fix itself so it does happen. CEL should come on KOEO, if not blown bulb or instrument cluster, wiring issue.
 

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I'm feeling vacuum leak on this one.

Is there any difference in how it runs at cold start vs. hot start?

Does the shaking happen every time you return to idle, or only intermittently?

FC
 

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Cylinders 1 & 5 corespond in that they receive firing signal at the same time. If you are sure the coil is good, I would suggest testing/inspecting the signal wire from the coil back to the PCM.
 

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Cylinders 1 & 5 corespond in that they receive firing signal at the same time. If you are sure the coil is good, I would suggest testing/inspecting the signal wire from the coil back to the PCM.
^+1

The Yellow/Black wire from the coil is the control wire for Cylinders 1 & 5 going back to pin 26 on the PCM.

The first test I would do is to make sure the PCM is firing the coil. Unplug the connector from the coil. Hook one side of a test light to the positive battery terminal and the other to the pin for the Yellow/Black wire. While cranking, the light should be flashing. If the light does not come on at all either the wire has been completely severed somewhere or your PCM is bad. If the light stays on solid, there is either a short to ground in the wire or the PCM is bad.

Should the light not come on at all, you can test the wire for continuity by testing the resistance across it from the coil connector to pin 26 on the PCM connector. It shouldn't be more than a few ohms. If it shows infinity, the wire is severed somewhere. You can check for shorts by checking the resistance from either side of the wire to ground with both connectors disconnected. If it shows anything but infinity, there is a short to ground somewhere. If the test light wasn't flashing during the crank test, and the wire tests good for continuity and doesn't have a short, the PCM is the likely problem.
 

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Discussion Starter #10
So... Connected a test light to yellow/black wire, no flashing. Tested resistance on the yellow/black wire, about 1 ohm. No short to ground/break in wire.

I got a used PCM but after installation the car won't start. Is the used PCM I have a goner or is there some other issue I'm not grasping?
 

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So... Connected a test light to yellow/black wire, no flashing. Tested resistance on the yellow/black wire, about 1 ohm. No short to ground/break in wire.

I got a used PCM but after installation the car won't start. Is the used PCM I have a goner or is there some other issue I'm not grasping?
Did you have the new PCM programmed to your PATS keys?
 

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:suicide:

I underestimated how difficult this problem would be...

So to reprogram the new PCM to be accepted by PATS I need to purchase software or take it to the dealer for reprogramming?
Yes that would generally be the answer. It is also possible to ship your old PCM that has the bad coil circuit out and have them suck the PATS info out of the old pcm and then flash the new PCM with the PATS and proper PCM catchcode for your vehicle.
 

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I struggled with these cylinder misfires for months on my 2001 duretec. Changed plugs, wires, ignition coil, PCV hose with no luck. What finally solved the problem was new upper and lower intake manifold gaskets. Apparently had vacuum leak from there. After I fixed that, car's been running great for last 6 months. Gopoint technology app for I phone was a great help for reading codes and live data from O2 sensors.
 
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