2000 grand marquis.trac control light on or digital temp elevates ch.engine came on. car running rough.#5 plugs mis-firing any ideas?


Asked by Mar 19, 2013 at 03:08 PM about the 2000 Mercury Grand Marquis LS

Question type: Maintenance & Repair

After accelerating at a very high speed for a short distance 1/8 mile. can start hesitating, the trac control came on then off then the temp gauge went up then back to normal. car was very reluctant to accelerate farther. 60mph to80mph back down "bout 50mph,curb struggling above 50mph. had codes retrieved. #5 and#8 spark where not working properly. would replacing spark plugs remedy problems or could there be a common issue with the 4.6l engine.95k was excellent condition. most miles are city 60% highway 40%. could there be a computer issue? how difficult for DIY? thanks Andre' C.

15 Answers

please have your trouble codes from yourautomotive scanner...then we can proceed-

3 out of 3 people think this is helpful.
Best Answer

Thank you, 2000 Grand Marquis troubleshooting codes p0305 and p0308 I also noticed the auto overdrive light flashing for awhile? go figure!


My 2000 Marquis is doing the exact same thing and nobody can tell me what the problem is. The only difference is that my car isn't throwing an engine light or any codes...Checked all wiring/fuses/relays and all seems good. People are hinting at the PCM, and everyone is telling me "its some kind of electrical problem"...well no shit sherlock! Everything on this car is electric, including the digital dash/gauges. Nice to know I'm not the only one with this issue.

6 out of 6 people think this is helpful.

Let me know if you got it figured out. Thanks

1 out of 1 people think this is helpful.

...as I suspected, the EGR valve is not operating properly, either the vacuum tubing is butyl and old and needs to be replaced, or the valve itsef is boggered and needs to be checked for smooth operation, a bath in kerosene? replacement 'cause their cheap?

this device is supposed to dump exhaust fumes on decel, unfortunately has given up the idea and is performing what we call a "dutch oven"...so what needs to happen is the valve should be operated manually, apply 12volts or draw air to activate, and see if the flapper inside works, obviously it does not open up on deceleration....no vacuum lines to the intake, exhaust...how this thing is plumbed will be on a chart on your hood or cowl....check back if you can't find it.

price it out~...thankyou very much!


I gotta ask what makes you think its the egr? Those codes are for misfires. I don't understand how the egr would affect the traction control. Please explain. Thanks

2 out of 2 people think this is helpful.

I understand an egr can cause the misfires but don't understand the TRAC light issue

1 out of 1 people think this is helpful.

well honestly cannot speak for the TRAC light which uses sensors in each wheel to apply each brake without you having anything to say about it...no the engine not idling properly, has no acceleration, poopey smellin exhaust and bad performance wreak of an egr problem, and perhaps it isn't and something as easy as a PCV valve (you could see if this greasy one-way street is workin' too)-

1 out of 1 people think this is helpful.

quickly read those numbers and they were all part of the 'fun-pak- o' trouble, mentioned in that trouble was mentioned the maf (which sensed before the egr, and the map (which senses after the egr), but the egr itself is the first line of trouble as it sees exhaust fumes and shunts them with every push of the accelerator, the maf and map help decide you enrichness of combustion amongst other sensors like 02 sensors before and after the catalytic converter----all this much ado, if the CO is bein transmogrified into CO2 using rare earth elements, fragile and subject to the best parts choked with carbon do actually make a difference as it is practically impossible to die from co2 poisoning ,rather the lack of 02 that you need to stay alive and breathe etc...

1 out of 1 people think this is helpful.


1 out of 1 people think this is helpful.

The trac issue, yes the magnets in the wheels have fallen off and sensors cannot sense the rpm's and correct the situation by applying brakes...I guess if you're driving on an icerink this would be handy~ gotta have this fixed? your call my friend but all cars thruout history "tuffed it" without one of these systems who's mission in life is to break down and add a level of complexity that we never wanted in the first place.

20merc00, the traction control system is a newbie in the automotive world, never used to be this common, and now it's the cause of many hours wasted tryin' to make it work properly...ain't worth it in my humble opinion- my latest painting will sit above the main counter at "the compasson center at clearlake" they are currently displaying full-time 12 of my artworks-


My trac ctrl light is on in my 02 grand marquis in when i start it up an pull off it will staul in the ctrl light will start blinkin in like 5-10 seconds it will go back to diving regular..but the trac ctrl light been on for a min..wat could it be??

3 out of 3 people think this is helpful.

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