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uniqs
2005

SysOp
join:2001-04-18
Atlanta, GA

4 edits

SysOp

Member

Ford Lincoln 4.6 DOHC Bucking Mystery Solved

Car developed a slight but consistent bucking under acceleration above 3k rpm. No codes.

After testing the coils, changing the plugs, changing the throttle body position sensor, cleaning the mass air flow sensor, cleaning the injectors the bucking persisted.

It turns out it was the battery. The battery voltage was testing good, but had corrosion hiding under the negative terminal and two of the battery cells were low on water.

Topped off the battery and cleaned the terminals. No more bucking. MPG went up, 18 city, 24 hwy

1999 Lincoln Continental 4.6 DOHC v8 41k miles

LazMan
Premium Member
join:2003-03-26
Beverly Hills, CA

LazMan

Premium Member

Doesn't sound right, to be honest...

Once the engine is running, the alternator should be carrying the load; not the battery. In theory, you can even take the battery out of a running car - although I don't suggest it.

But, hey, if your problem's fixed...

SysOp
join:2001-04-18
Atlanta, GA

4 edits

SysOp

Member

Not on the ford modular 4.6. The voltage regulator must be working correctly before the alternator will charge. (It requires 12v from the battery to function correctly.)

I tested the alternator with everything on at idle and it was charging. However, the issue was always above 3k rpm. Perhaps because the battery had 2 cells low on water, during hard acceleration the voltage would drop below 12v and the voltage regulator was not activating the alternator.

I also no longer get shocked when exiting the car! So a bad ground and a week battery were the culprits.

MooJohn
join:2005-12-18
Milledgeville, GA

MooJohn

Member

Wish that was the problem with mine!

Mine is going to be the torque converter. Oh sure, I could luck out and find that it's the lockup solenoid but my life doesn't work that way! Any time I'm barely on the throttle it jerks as it tries to engage the torque converter. Any other throttle position is fine.

BTW, if you need coils, the Summit Racing house brand is only $180 for a set of 8 and they're very well made.

My 2000 Continental - SuperChips programmer, intake, and some tunes.

Join us at the Lincoln vs Cadillac forum and/or the Lincolns Online forum
Tig
join:2006-06-29
Carrying Place, ON

Tig

Member

Check the torque converter to flex plate bolts. I've had issues with two different cars. If they loosen, they get real sloppy when coasting and the engine and drive train speed are close. It will buck and in one case, mine also sounded like a bag of hammers.
If you think it's the lockup solenoid, just unplug it and go for a test drive.

Ghastlyone
Premium Member
join:2009-01-07
Nashville, TN

Ghastlyone to SysOp

Premium Member

to SysOp
My 2dr Tahoe had a similar problem. I'd be cruising along and then suddenly lose power, or even die. I constantly showed a low voltage on my gauges. I even removed the Alternator and brought it down to a shop to get tested. Everything tested okay.

I stopped and checked over the motor one day and just happened to grab the power wire that ran across the fan shroud that went to the ECM, and it was burning hot. I knew right away there was a bad connection.

I got home and stripped the wire new, cleaned the battery terminal and reconnected. It fire right up and voltage was readin right under 14v. Drove down the street and it was like a new truck.