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2001 Mercury Marquis engine misfire

Is it neccesary to remove the intake manifold to replace the sensor that causes the computer to put the engine into the “linp in mode” because of overheating?



No

Thanks for your reply. I did not think so but a local ford dealer did. He charged me over $400.00 to replace that sensor. The dealers are not selling new cars so I guess are sticking it to us for repairs. BEWARE

It could have been necessary to remove the intake manifold to repair a leak which caused the overheating. Why not report, word for word, what the dealer told you. I think there is some lose of communication.

I agree with Hellokit as usual. The complete story might clear things up.
And what limp mode sensor are you talking about?

The 4.6 engine can be a bit difficult to service.

I may have answered to quickly. The heads were changed significantly in 2001 and I vaguely recall a change from one to two temp sensors (one for the dash and one for the PCM) at some point. My '99 manual shows $21.33 for the part and 0.5 hours for the one sensor that it has.

I don’t have access to the 2001 manual. Ask your question at www.crownvic.net for a definitive answer.

Note that long before 2001 Failsafe cooling. As the engine starts to get over temp, half the cylinders are deactivated. The deactivated cylinders are getting air but no fuel and this cools the engine somewhat. The care is driveable. It it gets too hot, it shuts off.