Mechanics

LINCOLN TOWN CAR MECHANIC PROBLEM

1998 Lincoln Town Car • 64,000 miles

Problem: Drove 115 miles upon purchase and pick up. Drove perfectly for 115 miles of 124 for total trip. Felt a buck like a tight shift at 65 mph and drove ok for 2-3 miles. Car started bucking and motor stalled at 65 mph. ¾ Tank of fuel on board. Coasted in neutral and started car. Back into drive and went ½ a mile and stalled again. Cranked good, was trying to start but wouldn’t, tried again and it started. Got off parkway and drove home 4-5 miles on back roads and made it. Drove it a day or two later 16 local miles with no problem. The next day drove it 8 local miles ok. On the way home on a straight stretch I floored it up to 65 mph and started to coast and it started bucking and stalled. Coasting at 55 mph I put it in neutral and it started up. It did it 2-3 more times at different speeds and I got home. The next morning my mechanic changed the fuel filter. The fuel pump appeared new ( Airtex ) so he did not change that. I drove it next day and the same thing happened.
CAR NEVER THREW ANY CODES AT ANY TIME !
During these episodes the Check Traction light would come on. Once in a while the
airbag light would come on. Upon restart they would go out till the next time.

1 Changed fuel filter . Ng
I have a perfect running 2001 Town car so
2 Swapped all fuel pump relays from 2001 to 1998 drove car ng
3 Swapped throttle position sensor with 1998 drove car ng
4 Swapped map sensor with 1998 drove car ng
5 Swapped new battery from 2001 to 1998 ( internal short? ) Drove car ng
6 Ran new ground wire from alternator on engine to neg battery post and cleaned
grounds at body of car in 1998 drove car ng
7 Ordered new Motorcraft Crank Position Sensor and replaced it. Upon start up and
a test run car was shut down and he read the codes. It showed a code for the pats key
system but the mechanic said it had nothing to do with the problem He re-set the
computer. Drove car ng
8 Mechanic suggested installing fuel pressure gauge and watch it while driving. Did
that.
At idle speed gauge shows 35 psi. While accelerating pressure rose to 40 psi. Always
stayed between 35-40 psi while driving. Car began to buck, sputter, catch, sputter,
then stall. At the same time gauge started flickering in rhythm to the bucking and
stalling but never went to 0 psi or even below 35 psi but as she was flickering the
engine was bucking and surging in time to the flickers on the gauge. While trying to
start the car it would crank and try to start like it had no fuel and would then catch
and run fine again still showing 35-40 psi on the gauge
.9 The 2001 Town Car ran fine with the swapped TPS and battery and MAP sensor.
10 I took the mechanic on a test drive with the fuel pressure gauge still attached and he
saw for himself the gauge flickering in time with the bucking and stalling. Because
the gauge never went to 0 psi he felt it was not a fuel pump issue. He thinks it a bad
connection some where and needs to be traced.


11. I spent a couple of hours under the hood disconnecting every connection I could
find, checking them for signs of corrosion, overheating, loose wires, shorts against
metal pipes or the body of the car, moved every harness up and down, side to side in
case wires were touching something they should not. I pulled every fuse, every
relay, turned over the boxes where they plugged in looking for loose wires corrosion
or foreign substances and anything else I could find. I undid the main harness to the
body of the car, I undid the harness to the ECM, checked them for any signs of
corrosion or moisture etc and found nothing. I cleaned up and took the car for a test
drive. N/G Same symptoms. The car starts normally. As I drive off I may get a
“buck” which feels almost like a tight shift or the torque converter locking up late.
The car accelerates fine and shifts fine. When I get to a long stretch of road I will
take her up to 60-70 mph and she accelerates fine. When I back of on the gas to
maintain cruising speed or decelerate is when I can expect to start to feel the
bucking, spitting, unevenness and when that starts it will throw the “check trac”
light on and as she still acts up the motor will die at 60 mph or less. I can put in
neutral and restart while coasting and she may run for a minute or stall right away.
If I pull over and start it and drive away she will stall a couple of times again, restart
and die again but if she catches and I drive it back home slowly (20-30 mph) I will
probably make it the 3-4 miles back or sometimes she will stall a couple of more
times but I will get her home.
Avatar
Biglongone
January 10, 2013.




Check out the related content below while we wait for the question to be answered by a professional mechanic.


AD