Strange problem...to me.

Recently I had an issue with the car not wanting to start, it did what it does when the battery goes bad (no noise, nothing turns on, etc). I opened up the hood and noticed the battery post had a lot of corrotion. Proceeded to clean it pretty good, connected the terminal went to start the car and it started. Idle was fine, I let the pcm re-learn the idle (or what ever it's called in the manual). Went to drive it and the car was seriously underpowered as if it was running on 4 cylinders or something like that. It would rev up to 4000 rpms before changing to the next gear. Then the check engine light came on. So I went to autozone got the battery tested and it was bad, then I got them to check the pcm to see what code it was throwing and it is giving me a "bad iginition coil 3".

What did I do wrong. Is this a "side effect" to a battery being bad?
Cars can have some weird problems like when my 82 transam's alternator was going bad it was making the choke for my carburator act up.

I hope the issue I'm having is clear, any help would be appreciated thank you.

Year and engine (12V, 24V, 32V) please. Sounds like you either have the Duratech (24V) or SHO.

The coil problem is probably just a coincidence with the dead battery. Did the battery fail the load test, or did it indicate one or more weak cells? If the fault was due to a bad cell, then you may have had too low of a voltage to keep the PCM working reliably.

You don't mention that you actually replaced the battery. If not, replace the battery and see if it makes a difference. If you did replace the battery and the power issue is still present, then you need to get the actual code. I doubt the code was for coil 3, but maybe a misfire on cylinder #3? This code could be caused by a bad fuel injector as well, which again is probably just a coincidence that it happened the same time as the bad battery.

Oh, also, do you have factory style battery cables, or a temporary bolt-on end? If you have a temporary type, you may have corrosion in the cable/connection which could be causing a voltage drop from the battery to the PCM.

-Rod

The car is a 1998 taurus 3.0 engine. I believe the battery is 12v. I just got it replaced at Sears today but the problem persists. The battery tested as unable to hold a charge. It has factory style battery cables the possitive side is about 5 or 6 months old. The code that I get is P0353 which reads Ignition coil no.3 primary circuit fault.

Thanks for the response.

Chris

We had one that had a P0352. We checked all the wiring and the coil per Ford shop manual and found the PCM was the fault. The test is not quick or easy . I believe shorod has the information for you if you want it.

Sorry, but 12V, 24V, and 32V I was referring to the number of valves in the engine. The 3.0L can have either 12V (Vulcan) or 24V (Duratech). The 32V is in the SHO.

As for the possible causes of a code P0353, the service manual lists:
Diagnostic Trouble Codes (DTC) P0350 through P0360 are ignition coil 1 through 10 primary circuit faults.

Possible causes

-- Open or short in Ign Start/Run circuit.

-- Open CD circuit in harness.

-- CD shorted to ground in harness

-- Damaged coil.

-- Damaged PCM.

l Disconnect coil #3 for P0353.

l Connect incandescent test lamp to both pins at the coil harness connector.

l Disable fuel pump by disconnecting inertia fuel shutoff switch.

l Observe incandescent test lamp while cranking engine.

If the test lamp blinks during cranking, the drive to the coil is good. If not, then you will next need to determine why it is not blinking.

We're going to take baby steps here, or if you want to private message me with an e-mail address for you that can accept PDF attachments, I can forward the relevant sections of the service manual troubleshooting steps to you (as way2old suggested).

-Rod

Thanks for the information guys. Sorry I haven't been able to reply sooner is just that I went back to school and I haven't had a chance to do anything else. The car still has the problem.
Shorod, how do you disable the inertia fuel shut off switch. And when you say "CD" what are you referring too?

Thanks a million for the help.

Chris

You can disable the inertia fuel pump cutoff switch by unplugging it. The switch should be located in the trunk of your Taurus, on the driver's side behind the trunk liner. There is probably a sticker in the trunk telling where the little hole is to reset it. You'll need to be able to get to the wiring, so you'll need to remove the liner.

"CD" in the context above is the "Coil Driver."

-Rod