rough idle

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Sep 9, 2003 | 01:12 PM

Herm

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Joined: Sep 2003

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rough idle

1989 E350 with 460 fule injected motor 60,000 miles (Fleetwood Jamboree Motorhome). I replaced plugs, wires, rotor, cap, air filter, PCV, 5000 miles ago last year when I bought it - used all OEM parts. Idled very smooth until last week after I returned from a 200 mile trip - now idle is very rough - can hear slight pops/misses at exhaust.

Also noticed exhaust pipe has black soot (not sure if this is new)

Would appreciate any ideas/thoughts/possibilities on what is causing rough idle or suggestions for further troubleshooting - I'm a pretty advanced home mechanic but this engine is new to me.

THANKS - Herm

Sep 9, 2003 | 08:46 PM

powerfull

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Joined: Nov 2002

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From: Wapanucka USA

rough idle

hey my dad has the same problem he said its his o2 sensor in the intake but were to lazy to fix it

Sep 9, 2003 | 11:31 PM

c_rossman

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Joined: Mar 2003

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From: Cloud USA

rough idle

Check the vacuum line going to the MAP sensor, if it is leaking, the motor will run rich because of less manifold vacuum.

Sep 9, 2003 | 11:33 PM

c_rossman

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Joined: Mar 2003

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From: Cloud USA

rough idle

The computer ignores the 02 sensor at 3/4 and above throttle positions. IF it runs good WOT but not part it maybe the O2

Sep 10, 2003 | 01:35 PM

f350bronco

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Joined: Jan 2001

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rough idle

If it the problem started suddenly, I would look for vacuum leaks. Cracked or lose hoses are a very good place to start.

We are assuming the the engine otherwise runs fine.

John