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Ignition coil problems-perhaps

I have a 2000 Lincoln Continental Cartier with the 8 cylinder engine, auto transmission. Driving about three weeks ago when the car lost power and would not go over 40 miles per hour, but the engine was not racing. It just would not respond to the accelerator. The check engine light had been on for two months. Earlier the read out indicated a bad catalytic converter so we were supposed to drive it until it lost power. Had the converter replaced, no fault lights appeared and three days later, the same thing happened. Took it back, no faults and was referred to the dealer. Dealer was stumped but virtually guaranteed that the problem was the other catalytic converter, even though no fault lights were on. Replaced the catalytic converter in the second muffler and it happened again three days later. Back to the shop, they pulled everything they could think of: mass airflow, sensors, throttle position sensor and no luck. Same story, drive about 3-6 miles at 55 mph and suddenly you can’t go over 40 and the engine will not respond. Drive back the shop and the situation may or may not begin to improve. Sometimes you stop at the light and take off and can go 50. Sometimes the problem disappears. Seems to happen as the car warms up. The shop sent it back to the dealership and they went through full diagnostics: no lights, no faults, the computer says it is OK. Mystified, they talked to the technicians in Michigan (?). Our local shop found that the ignition coils were not to spec when the problem is occurring but when the engine is running correctly the specs (ohm readout) is normal. Their solution is to replace all 8 coils ($1200) even though they agree that the problem does not match the symptom. My suspicion is a faulty computer or software glitch in the computer. Thoughts??

I always suspect the computer in cases like yours. I wonder if all your system monitors are in ready status. I wonder about a lot more things too.

Now that I’ve seen what I posted (it’s June now), it looks like I’m not very helpful. How did the repairs go?

Ford has a TSB out on how to stress test the coils. A resistance check tells you almost nothing. The OEM coils cost anywhere from $50 to $100 depending on where you get them. They are easy to change out yourself. It is possible from your symptom description that one or more of the coils is indeed your problem. A marginal coil can cause EMI noise that confuses the engine computer causing it to go into low engine power mode.

Any chance this could be a fuel pump going in and out? A pump can be erratic in nature and I would think if coils were this much of a problem the ECM should be spitting out some codes for coil faults.

I can’t say for the Continental, but I know that on the LS, marginal coils can cause all sorts of problems without setting a misfire or coil fault code. That said, a fuel pump problem is a good guess too.

OK…so far my mechanic has replaced the fuel pump without success. Still seems to me that when the coils and the pump are failing during the problem that they may be getting faulty inputs from the computer.

Dealer says they will replace the 8 coils and guarantee it will fix the problem. If not they will fix it again. How far do you think they will really go. For example, if the fix the 8 coils and the problem recurs in 4 weeks, will they still fix it??

So the fuel pump was replaced and the problem recurred in the test drive. We waited three weeks for a new mechanic to take a look. While driving to the shop, no problems. Have driven the car for a week and nearly 300 miles and no issue has shown up again.

OK the problem did happen again. Changed the mass air flow device, sensors in the engine, then the wiring harness. Turns out the sensor to the trac on/off was bad. When it kicked on, the engine slowed almost to a halt. Disconnected the trac device so it always shows “trac off” and no more engine problems!!

This is a good point to remember. Trac Control kills the motor until traction returns. A bad sensor in the trac system can mimic all kinds of problems. In this case it sent you on a wild goose chase including many trips to the dealer and lots of new unneeded parts.

Took a specialist in Lincoln’s from April to August to finally solve this one. He said to drive it for 30 days before I came to ask for the bill. 30 days is about over so we will see the monetary damage report soon!