Mechanics

MISFIRE

1993 Ford Aerostar

Engine Performance problem
1993 Ford Aerostar 6 cyl Two Wheel Drive Automatic 167000 miles

My Aerostar runs great around town, but on the freeway, particularly on un uphill grade, the engine starts to really gut out/misfire. It seems to happen after the tranny shifts into its 4th gear/overdrive. Big loss of power.

Also, do you know where the fuse is that covers the radio?
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Brioedmonds
June 17, 2009.




A badly needed tune-up could cause your problem to include be below

Misfires can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include: Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

The fuses that powers the radio is the fuse no.8 15amp and fuse no. 11 15amp.

Tiny
Rasmataz
Jun 17, 2009.
Thank you for your reply to my question. I think you are right.A full tune up is probably in order. What a nightmare reaching those plugs and plug wires. What's the secret to changing plugs and wires?
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Tiny
Brioedmonds
Jun 19, 2009.
Jack the vehicle up and let it sit on stands. Make sure you have Ford or Autolite double platinum plugs plus some copper anti-seize (for the plug threads). It's a good idea to change the cable at this time too. (Use Motorcraft or Autolite only). Remove the front wheels and the well cover (located inside your 'star; between the driver & pasenger seat, right on the floor, below the radio). You sgould have enough room to change the all plugs. Access from underneath

Tiny
Rasmataz
Jun 19, 2009.
Rather than removing the wheel, iner cover etc. On my 4.0L I removed the altermator and throtle cover and accessed the passenger side plugs and wires. Replacing wires one at a time is a real time-saver

Tiny
19pinto71
Jun 21, 2009.

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