Cylinder Missing?
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New User
Joined: Nov 2004
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From: Evansville, IN
Cylinder Missing?
My 89 bronco 302 runs fine when I first start it up but after 5 minutes of driving it starts to vibrate a lot and feels like it is missing a cylinder or something. The engine has been rebuilt and has about 30K on since then. The auto tranny has 200K+. I have heard anything from clogged catalytic converter to leaking intake manifold. Any ideas?
Lead Driver
Joined: Sep 2002
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From: Gateway to the West
Any codes stored in the computer? This is where I'd start. Knowing what the on-board computer knows helps diagnose without the wild goose chases.
Haynes manual tells how to get the codes using a paperclip or you can have a local parts suply store pull the codes for you. Autozone, NAPA and a few others will do it for free.
Haynes manual tells how to get the codes using a paperclip or you can have a local parts suply store pull the codes for you. Autozone, NAPA and a few others will do it for free.
Posting Guru
Joined: Jun 2004
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From: just outside of Phila.
I don't really know how likely this is or whether it would apply here, but check your spark plug wires, first to see that they're all plugged in obviously, then for arcs (look under the hood at night) to see if there is a break in any of the wires, then check to see if the #7 wire and the #8 wire are on top of eachother. If they are, loom them up away from eachother.
Posting Guru
Joined: Jun 2004
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From: just outside of Phila.
did you check the plugs yet? I have an 88 302 and had a similar problem. Only suggesting plugs because it's free to lift your hood and look, and if anything, move some wires around. I find the codes to be confusing and send me in all kinds of directions.
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From: Front Range of Colorado
Depending on what you find with other problems and fixes. You might have an injector pumping out gas, that wipes the cylinder and you lose compression on it. A squirt of oil and compression should return.
Pam
Pam
Lead Driver
Joined: Oct 2004
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From: Central Oregon
To check the plug wires, youcan use a timing light. Just hook the inductor on each plug wire and watch the light to see if the plug is firing. By watching the light for a time you can see if it is misfiring or firing all the time.
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New User
Joined: Nov 2004
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From: Evansville, IN
It was the plug wires. They were against the exhaust manifold and had gotten a hole. Replaced them with motorcraft wires and got new champion platinum plugs. Thanks for the advice.
