1991 Lincoln Town Car Shakes and Backfires Fix

1991 LINCOLN TOWN CAR

VDAWG

MEMBER
2 POSTS

Hi ,i have a 1991 lincoln towncar executive with a 4.6 ohc v8 141,000m,i have had this car for 4 years and no problems until now,i was recenlty going to sell the car(it was running fine)so i took it to the car wash to spray down the engine with enginebrite to get at least some of the dirt and oil off,after that i drove it to a gas station and it was still running fine,it drove fine all the way home,i let it sit for about a day ,then i went to start it and it started up fine but was now idling a lil rough,i looked at the engine ,it looked ok,but when i drove it down the block it started shaking real bad and backfireing(popping) but only when im starting out or going about 5-10 mph, the transmission seems to shift ok, could this be faulty wires?plugs.distruibuters? or something else the exhaust is also spitting out water but i think its always done this. Note:i have cleaned MANY engines this way and this one in the past and have never had a problem. any help would be greatly appreciated thank you.

Feb 20, 2006 at 10:33 AM

PEPPERMRJ

✓Experienced Mechanic
1,158 POSTS

I would look/listen for a vacuum leak. Sounds like something came loose/off. Check the PCV setup closely.

Good hunting and let us know. :)

Feb 20, 2006 at 11:36 AM

VDAWG

MEMBER
2 POSTS

Hey thanks guys,i went ahead and just about pulled my hair out tryin to find somthing wrong :evil: (vacuums/fusable links/modules/etc..etc..)i pulled the codes and i was getting an egr little or no voltage (345) but that wasnt it,i recently smogged the car ,it passed and that wasnt even connected,problem came after. so i decided it had to be the ignition system,i checked the plug wires with a cool lil tester i found at kragen/checker auto for 4 bucks(sweet !) wires were all fine,but when i pulled the spark plugs,they had been fouled and rusted. due to me in my infinite wisdom filling the plug holes with water. although,the plugs should have been properly installed with some sort of anti rust/sieze to seal them ,the previous owner did not plus the gap was at .060 not at .054 like they should have been,i was surprized it ran so well like that before,NOTE:be very carefull not to let any WATER! debris or oils,fall into your combustion chambers,i used an aeresol electronics air duster to clean them out before i took the plugs out because i do not have an air compressor with a hose to blow them clean,anyways ,new plugs ,problem solved ,thank you ,hope this helps someone else . god speed

Mar 29, 2006 at 8:24 PM

PEPPERMRJ

✓Experienced Mechanic
1,158 POSTS

Thanxs for the update.

Happy motoring :)

Mar 30, 2006 at 10:20 AM

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Suggested Repair

Replace the fouled, rusted spark plugs contaminated by water in the plug wells during the engine wash, and set the gap to 0.054 inch. Keep water, debris, and oil out of the plug holes and combustion chambers. If symptoms remain, inspect for a vacuum leak and check the PCV system.

Conversation Summary

A 1991 Lincoln Town Car began idling roughly and shaking and backfiring at about 5-10 mph after the engine was sprayed with cleaner and the car sat overnight. An expert suggested listening for a vacuum leak and checking the PCV system. The owner found an EGR low-voltage code that was not the cause, confirmed the plug wires were good, and discovered the plugs were fouled and rusted from water in the plug holes and gapped at 0.060 instead of 0.054. New spark plugs solved the problem.

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1991 Lincoln Town Car Shakes and Backfires Fix

Suggested Repair

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