Rough running engine
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Freshman User
Joined: Jun 2001
Posts: 29
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Rough running engine
I have a 91 Ford Explorer 150K miles on it. I notice at low RPMs, specifically when the overdrive kicks in and I'm driving 45-50 MPH, the engine really dogs and shakes. Really noticable if I'm trying to accellerate slightly up a hill. I kick it down and get into a higher gear and everythings fine. I've cleaned out the fuel injectors, replaced plugs and wires, drained and refilled the rear axle. U Joints? I think they would rattle at all speeds and this is only at low RPMs. Tranny? Could overdrive be flaky at low rpms? I've had two tranny shops test drive it and they say the tranny and torque converter is in good shape.
Any ideas on troubleshooting this?
Any ideas on troubleshooting this?
Posting Guru
Joined: Jan 2001
Posts: 1,124
Likes: 1
From: Rural Florida Panhandle
Rough running engine
I normally try to give advice only from experience, but since no one has answered, here is what I would try:
1 - Determine if the problem is in the engine or driveline. You can do this by trying to cause the symptom while stopped. Put the transmission in 2, so that the engine will be more loaded, (I may be wrong on this) hold the brakes firmly, and gently increase the engine speed to see if there is any abnormality. You may have to try several times.
If this fails, then check or have someone check the u-joints and other mechanical components again.
If the problem occurs while stopped, then the problem is in the engine - could be the coil bank, etc.
2 - Lock out the overdrive and try driving under the same conditions to see if the problem is in the transmission. You will need to put a similar load on the engine, just don't let it shift to overdrive.
Hope this helps.
Winford
54F100 5.0 HO, 88F150 5.0, 91 Explorer 4x4 5 spd, 98 explorer 5.0 AWD, 92 Mustang 5.0 5 speed.
1 - Determine if the problem is in the engine or driveline. You can do this by trying to cause the symptom while stopped. Put the transmission in 2, so that the engine will be more loaded, (I may be wrong on this) hold the brakes firmly, and gently increase the engine speed to see if there is any abnormality. You may have to try several times.
If this fails, then check or have someone check the u-joints and other mechanical components again.
If the problem occurs while stopped, then the problem is in the engine - could be the coil bank, etc.
2 - Lock out the overdrive and try driving under the same conditions to see if the problem is in the transmission. You will need to put a similar load on the engine, just don't let it shift to overdrive.
Hope this helps.
Winford
54F100 5.0 HO, 88F150 5.0, 91 Explorer 4x4 5 spd, 98 explorer 5.0 AWD, 92 Mustang 5.0 5 speed.
Thread Starter
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Freshman User
Joined: Jun 2001
Posts: 29
Likes: 0
Rough running engine
Thanks for taking the time to reply!
One of the shops that checked the transmission said the motor mounts were weak, but not needing replacement. Would that be a possible cause?
The engine runs rough when cold. I replaced the wires and spark plugs, fuel pressure regulator, and cleaned the injectors.
One of the shops that checked the transmission said the motor mounts were weak, but not needing replacement. Would that be a possible cause?
The engine runs rough when cold. I replaced the wires and spark plugs, fuel pressure regulator, and cleaned the injectors.
